noun, noun or participle which takes 'suru', intransitive verb
acting like a boyfriend; putting on boyfriend airs
Used when someone acts as if they are someone's boyfriend despite not actually being in a relationship. Often carries a negative or mocking tone. Can be used as a noun or with する to describe the behavior.
まだ付き合ってもいないのに、彼氏面するのはやめてほしい。
I wish he'd stop acting like my boyfriend when we're not even dating.
彼
It's annoying when he gets jealous and acts like he's my boyfriend.