Harry "Doc" Sagansky was a Jewish organized crime figure in Boston. Sagansky started off as a young graduate of Tufts dental school and quickly gave up his practice for the lucrative numbers racket. Not only was he a numbers bookie,but he became known as the top layoff man in the city.When far too much money was gambled on certain numbers, Doc would take the layoffs from other bookmakers.Doc became a millionaire and was regarded as Boston's biggest bookmaker. By Domenic Spinale

Nails, whose real name was Joe Snyder, was a Boston native connected with the Winter Hill gang.Snyder had been given the nickname Nails by the professional gamblers in Las Vegas, for his tenacity in dealing with point spreads on sports betting.He was considered "hard as nail" for never taking the worst of a point spread on ant gambling event.If Joe favored betting on a game at one particular point spread,and the number was not available,he would not make the bet.By Domenic Spinale

Stefano Magaddino, also known as The Undertaker, was born October 10, 1891, in Castellammare, Sicily. After being shot at in Brooklyn by the Buccellato clan, Magaddino relocated to Buffalo. In WNY, Magaddino set up shop and started a bootlegging business, allowing the Cleveland Syndicate and Moe Dalitz's "Big Jewish Navy" to smuggle illegal booze from Canada through Buffalo! And when any of his rivals or regular citizens got in the way and needed to be "disposed of", he also owned the the Magaddino Memorial Chapel funeral home! Yasmin Young

Benedetto Angelo Palmeri was born Jan. 12, 1878, to Francesco and Anna Caleca Palmeri in Castellammare del Golfo, Sicily.
Palmeri's violent tendencies resulted in a 1915 arrest for assaulting a police officer. He was convicted and fined $250. His reputation was enhanced by the nickname "Buffalo Bill," reportedly awarded to him because he wore cowboy hats and carried a holstered pistol. DiCarlo home page.

Salvatore "Tom Mix" Santoro of the Luchese family bore a resemblance to an old time cowboy film star called Tom Mix.

Colombo associate Joseph Luparelli preferred eating fish to meat.
Hence the name Joe " Fish" Luparelli.

Angelo Bruno's prohibition on violence earned him the nickname "the Docile Don".He became famous for settling disputes through compromise, both inside and outside the Family. His 22 years as boss were remarkable for their lack of violence.
Book "the Plumber"

Nicodemo Domenic "Little Nicky" Scarfo (March 8, 1929 – January 13, 2017) was a member of the American Mafia who eventually became the boss of the Philadelphia crime family after the death of Angelo Bruno and Phil Testa. During his criminal career, Scarfo was described by some as psychotic, cruel and vicious. From many accounts of his former criminal associates who testified against him, he would want to murder someone if he was shown the slightest bit of disrespect or even if he was stared at. wikipedia

On the subject of his height,Scarfo was particularly senstive.No reference to it was ever allowed,and though among themselves his associates referred to him as "Little Nicky" or "the Little Guy". No one dared to use these terms within his hearing. Book The Plumber.

John DiFronzo (born December 13, 1928), known as John "No Nose" DiFronzo is an American mobster and the boss of the Chicago Outfit. DiFronzo, a former enforcer and caporegime, first appeared in the criminal record in 1949. He got the nickname "No Nose" because he sliced off part of his nose while jumping through a window during a 1949 clothing store burglary. Reportedly, the police gave him back the missing part which was almost perfectly restored. Wikipedia

Angelo J. "The Hook" LaPietra (1920–1999) was a Chicago mobster and member of the Chicago Outfit, involved in extensive loansharking operations in the city's First Ward during the 1970s and 1980s. He earned his nickname "The Hook" due to the way he murdered his victims—those that did not, or could not pay up. He would take his victim—bound and gagged—and hang him on a meat hook, (piercing the victim's rib cage with the meat hook) and then torture him to death with a blow-torch. The torch would not actually be the cause of death. The victims most often died from suffocation. wikipedia

Ciment, did you see my post? I was hoping you might know.

My apologies, I must of overlooked it by mistake.
Yes, it would be funny to watch their facial expression. Who knows may some were probably killed for uttering such name.
But I could picture a scenario of mafia soldiers having a conversation that is taped by the FBI and said tapes being released in court. Then having their mafia boss read in media reports what his unwanted nickname was.

"Patty the Pig" — for Patrick DeFilippo, accused in a federal indictment of being a member of the Bonanno family. This was the pre-diet nickname for a Bronx man who used to weigh roughly 300 pounds.

"Patty from the Bronx" — DeFilippo's post-diet nickname.

-taken from the Chicago syndicate web site.

"Good Lookin' Sal" — for Salvatore Vitale, an acknowledged Bonanno family member and government witness. Court records indicate he came up with the name himself and urged underlings to use it.
--taken from the Chicago syndicate web site.

Mikey Scars" — for Michael DiLeonardo, an acknowledged Gambino family member and government witness. From scars he received in a childhood accident.
--taken from the Chicago syndicate web site.

"Nicky Eye Glasses" — for Nicholas Marangello, a convicted member of the Bonanno family. His glasses were very thick.
--taken from the Chicago syndicate web site.

"Kid Blast" — for Albert Gallo, a convicted member of the Gambino family. He was known for enjoying parties.
--taken from the Chicago syndicate web site.

Salvatore ‘Toto’ Riina, one of the most feared Godfathers in the history of the Sicilian Mafia, has died.

The 87-year-old, nicknamed ‘The Beast’ because of his brutality, had been serving multiple life sentences for his role in a number of high-profile murders as a Cosa Nostra boss.Also known as "Toto u curtu"(shorty)

Salvatore Maranzano was nicknamed "Little Caesar" because he was a Roman military history buff, had a bust of Caesar in his office, regaled about Caesar's exploits, and like Caesar, he was stabbed and killed.

"Phil Lucky" — for Philip Giaccone, a convicted Gambino family member. The name was unintentionally ironic; he was assassinated by a rival.
--taken from the Chicago syndicate web site

"Louie Bagels" — for Louis Daidone, a convicted member of the Lucchese family. He owned a bagel shop in Queens, N.Y.
--taken from the Chicago syndicate web site

"Mikey Y." — for Michael Yannotti, a convicted associate of the Gambino family. Easier than saying his last name.
-taken from the Chicago syndicate web site

"Richie from the Bronx" — for Richard Martino, a convicted Gambino family member. Apparently used to distinguish him from the many other Richies involved with the Mob.
-taken from the Chicago syndicate web site

Mobsters sometimes use nicknames with each other to avoid easy identification by the feds. The mob boss Vincent "Chin" Gigante (whose nickname was "Cinzini," short for "Vincenzo",) insisted that his name never be spoken aloud. His wiseguys were told instead to rub their fingers across their chin or, at one point, to refer to him as their "Aunt Julia." Meanwhile, the press dubbed Gigante "The Oddfather" after he began posing as a schizophrenic in the late 1960s.By Daniel Engber

BENJAMIN “BUGSY” SIEGEL
The feared, entrepreneurial mobster (he ran his first gang at 14 years old) had a tough time controlling his temper, which led people whispering behind his back that he had “gone bugs” or was “crazy as a bedbug.” Bugsy hated the nickname though, and if any of his guys called him that to his face, they would’ve probably lost theirs. From Lineup

CHARLES “LUCKY” LUCIANO
Luciano was top dog in New York City’s crime syndicate in the early 1930s, but his quick rise to power (by off-ing “Joe the Boss” Masseria) wasn’t the reason Lucky got his nickname. The way he told it, he narrowly escaped several attacks on his life, including the one that left scars on his face and a droopy right eye. From Lineup

My memory of why former New England mob boss Francis Salemme – had received the nickname “Cadillac Frank” was because at one time, he worked on Cadillac cars at a garage in Boston. Francis P. Salemme [Salemmi], also known as "Cadillac Frank" and "Julian Daniel Selig" (born August 18, 1933), is a Boston, Massachusetts mobster who became a hitman and eventually the boss of the Patriarca crime family of New England before turning government witness. Wikipedia

Vincemt "the schemer" Drucci was on of the leaders on the North Side Gang of Chicago: After serving his country in the military, Vincent Drucci at a young age is involved with crime. He begins by robbing telephone coin boxes when he is noticed by the Northsiders. Nicknamed "The Schemer" for his various plans such as how to overthrow the government by killing everyone in command and becoming president of the U.S.
Drucci is a wacky fun gangster, at least to his co-horts. To others, especially rivals he was one tough torpedo to tangle with. One episode has him dressed as a priest on the sidewalk and as a couple walks by Drucci blurts out "You have a nice ass" As soon as they turn around to face the insulting Drucci he blurts out "Not you lady, your fellow!"

One time Dean O'Banion himself participated in the mayhem by pretending to kick the shit out of Drucci whilst in the priest outfit.

Other madcap jokes done by the druccmeister where done to drivers who delivered bootleg booze for the Northsiders. The driver would arrive at Schofield's and park his car out back and then drive off with the Northsider's truck in front for booze pick ups or deliveries. Once in winter time, Drucci went out back of the Flower shop and filled the driver's car full of snow. When the unsuspecting driver came out back to see his car, he was left in total shock. Drucci had shovelled snow inside his car right to the top. The driver was pissed off and Drucci was no where to be seen. When learning of this O'Banion laughed his head off but sympathized with the driver. O'Banion had to pay to have the car cleaned out.

Another joke performed by Drucci was the shoe game. Whenever someone in the gang had a new pair of shoes Drucci would yell "shoes!!!" and tackle the new shoe wearer to the ground while removing the new footwear and throwing it as far as he could. Hymie Weiss fell victim one day on the second floor of Schofield's flower shop. Drucci saw that Weiss had a shiny new pair on so he immediately tackled Weiss to the ground, removing his shoes and throwing them out the open window to the ground below. Coming up the street was a Northside truck driver who saw the foot covering missiles hitting the ground and the word "Shoes!" being yelled out.

Hymie stuck his head out and asked the driver to kindly retrieve the shoes and bring them up. Meanwhile, Weiss was calling Drucci every expletive available. Al Capone Museum

Joseph "Piney" Armone, also known as Shorty, (September 13, 1917 – February 23, 1992) was a gangster in the Gambino crime family who served as underboss. Born on the Upper East Side, Manhattan, Armone earned his nickname "Piney" in the 1930s by extorting money from Christmas tree vendors.[1] He was the younger brother of mobster Stephen Armone, an early member of the Mangano crime family, forerunner of the Gambino family.wikipedia

Anthony J. "Tiger" Cardarella (1926–1984) was a Kansas City, Missouri mob figure involved in large-scale fencing operations. Cardarella was the owner of Tiger's Records shop on Independence Avenue in Kansas City. He was also a suspect, along with Felix Ferina, in a gangland shooting for which he always insisted on his own innocence. Cardarella served five years in prison for receiving stolen property including firearms. He was noted for paying professional thieves and shoplifters to steal records from other record stores, such as Walmart. Wikipedia