closeted introvert

A person who defines themselves as an introvert but everyone views them as an extrovert or, a person who hates socialising but does it anyways for reasons like people pleasing or social anxiety

Them: you’re such an extrovert you talk to so many people
Me: nah I hate talking to people but I do it cause I’m a people pleaser

Them: oh so you’re a closeted introvert

Closet introvert

Someone that isn't openly the introvert they really are. Someone that comes across as bold to people that don't know them well, and mouthy to people that knew them growing up.

The introvert seemed like a bold extrovert to people that didn't know her well growing up, that was certainly her image with them, and because she benefitted from it in many ways, she wasn't going to tell anyone that didn't know her well from growing up around her that she wasn't actually an extrovert at all, she was a closet introvert.