But-boy noun
Used to refer to a man that often voices objections
I’d rather be a but-boy to voice my opinion than a man that says yes to everything.
You are such a but-boy. Can you agree with me even for once?
An intense argument
Not agreeing with or having an understanding of someone or something
The idea of the noun may be based on the meaning of “but” - a word used to introduce something which contrasts with what was said before.
To do domething based on your emotions rather than for rational reasons
I can't believe that Tom beat his classmate. He's always the one who let his heart rule his head.