Definition from Wiktionary, the free dictionary
sidekick (plural sidekicks)
- (informal) An assistant to another person, especially to one's superior or more important person.
2012 May 24, Nathan Rabin, “Film: Reviews: Men In Black 3”, The Onion AV Club:
- In the abstract, Stuhlbarg’s twinkly-eyed sidekick suggests Joe Pesci in Lethal Weapon 2 by way of late-period Robin Williams with an alien twist, but Stuhlbarg makes a character that easily could have come across as precious into a surprisingly palatable, even charming man.