1. In video gaming, an enemy seen at the climax of a particular section of the game. Also known as a boss.

2. In film, the lead actor.
Friend "Hey wow you finally beat that level!"

You "No I still have to fight the main guy!"

Friend "Hey, who was the main guy in True Romance?

You "That would be Christian Slater"
by Jorseman December 16, 2011
practically anyone as long as you're fine, play a sport, bash, or people just like you for no sensible reason.
hes a main guy
by mattiastoilet October 4, 2020
Gender neutral definition of anyone having the the lead on a job or project where the workflows are separated between people.

The lead actress of a movie.

Lead host of a podcast.

The foreman of a work crew.
by Jules Elysard September 8, 2022