Over the years, Iron Man had gone through a lot of things in the MCU, and that ultimately changed his perspective of the world. Starting off as a self-centered industrialist, he ended his arc as a selfless hero who gave up his own life for the safety of the whole universe in Endgame. The character had tremendous growth for the better, and while he still committed mistakes here and there, he always had good intentions.
While Iron Man's outlook drastically changed in the last several years of his life, one thing was constant—his witty humor. This has become the signature brand of comedy for the MCU with newer quippy heroes like Star-Lord (Chris Pratt), Ant-Man (Paul Rudd), and Doctor Strange (Benedict Cumberbatch) ing the universe. Tony loved engaging in back-and-forth banter, making him so fun to watch. Most of the time during these fast-paced conversations, he also snuck in funny nicknames, resulting in a long list since he debuted more than a decade ago.
Rhodey
In the first Iron Man film, James "Rhodey" Rhodes (Terrence Howard) pretty much played babysitter for Tony Stark. He had to keep his friend in check as they worked together on the launch of the Jericho Missile in Afghanistan. Whenever Rhodey was seriously exasperated by Tony's antics, the genius billionaire would smooth things over by calling his friend funny nicknames like "Honey bear," "Platypus," and "Sour Patch."
The Avengers
Following Tony's announcement he's Iron Man, Nick Fury (Samuel L. Jackson) actively sought him out Iron Man 2 shooting the offer down as he had bigger personal problems to attend to — he was dying from palladium toxicity from the arc reactor which was keeping the shrapnel out of his arc. During one of their conversations where Tony declined to the Avengers Initiative, he called Fury's project "Super Secret Boy Band," due to its under the radar nature and the team being ideally comprised of superheroes.
Black Widow
Introduced in Iron Man 2, Natasha Romanoff (Scarlett Johansson) was sent by Nick Fury to look after Tony Stark as they feared he was dying. She took on the disguise of Natalie Rushman and became Tony's assistant. She also promoted Pepper Potts (Gwyneth Paltrow) to be the new CEO of Stark Industries as Tony feared he would eventually die from the palladium poisoning. After Fury itted to planting Black Widow in his company, Tony called her "triple imposter," which refers to her impressive deceptive skills. This makes sense since she's a super spy.
Loki
Iron Man's first encounter with Loki (Tom Hiddleston) was during the God of Mischief's attack on in called Loki "Reindeer Games." Later on, as they transported him via the Quinjet, Tony once again took a jab at Loki's appearance; this time, he zeroed in on his long black hair, calling him "Rock of Ages." This is in reference to the Broadway musical/movie that features characters who have similar hairstyles.
Captain America
In their first-ever proper conversation in The Avengers, Tony Stark couldn't help but bring up the fact that Steve Rogers (Chris Evans) was frozen in ice for decades, which means the Super Soldier wasn't up to date on the modern world. When talking about this, Tony referred to Steve's time on the ice as him being a "Capsicle" which is a play on the word popsicle. Later on, in the same film, he poked fun at the Star-Spangled Avenger being a man out of time, calling him "older fellow" and "old man," which Steve technically was.
Thor
Before Tony, Captain America, and Black Widow safely brought Loki to S.H.I.E.L.D. at the start of The Avengers, Thor (Chris Hemsworth) hijacked their quinjet and took his brother, insisting he be tried on Asgard instead. This led to a brief battle between Iron Man and the God of Thunder in the forest. Not missing Thor's cape, Tony called him "Shakespeare in the Park" and proceeded to make fun of his costume. After they get better acquainted, Thor: Ragnarok.
Hawkeye
Clint Barton (Jeremy Renner) spent most of The Avengers under Loki's control, but once he got out of it, he ed Earth's Mightiest Heroes to defeat the trickster and his Chitauri army. At one point during the Battle of New York, Captain America gave out orders about what each member should do. For his job, Hawkeye needed to get up to a high point and asked Iron Man for a lift. Just before they flew up, Tony called Clint "Legolas"—a Lord of the Rings reference given that both characters use a bow and arrows.
Happy
Aside from directing the first two Iron Man movies, Jon Favreau also plays Happy Hogan in the MCU—Iron Man 3, he was promoted to Stark Industries head of security. During Aldrich Killian's (Guy Pearce) initial attempt to lure Pepper Potts into his scheme, Happy immediately felt something was sketchy about him. He video called Tony to notify him of the situation. Apparently a tech noob, Happy's forehead was all his boss could see, which earned him the moniker "Forehead of Security."
Trevor Slattery/Fake Mandarin
Iron Man 3 pulled arguably one of the most effective villain plot twists when it was revealed the film's Mandarin – a supposed global terrorist wreaking havoc around the world – was nothing but a paid actor named Trevor Slattery (Ben Kingsley). Upon learning this, Tony quickly came up with a string of nicknames for him such as "Sir Laurence Olivier" and "Meryl Streep"—two well-known actors. He used "Ringo" as well, referring to The Beatles member, since Slattery looked like him.
Killian's Henchman
Even when in the most dire situations, Tony couldn't help but make funny quips. After Killian's men held him captured, he talked to one henchman who had his long blonde hair tied at his nape. To make light of the situation, Tony called him "Ponytail Express," referring to his hairdo.
