Uses to describe someone who is just as naive or inexperienced as a newborn baby or someone who's only been in this world for a day.
I can't believe Jerry says Ford is a good manufacturer, he must have been born yesterday.
by D. Y. Vetz November 28, 2019
Something you say in order to tell someone that you are not stupid and are not easily deceived.
Mom: Timmy, what was that sound?
Timmy: Idk mom, it was probably Johnny masturbating again.
Mom: I wasn't born yesterday. Get your damn girlfriend out of your room.
by susanandvictor4eva April 24, 2015
A phrase meaning (often used sarcastically), i appreciate it, but please stop giving me advice, I know what I am doing.
Mother: Adrian go take a shower, then do your homework, not the other way a round.

Adrian: mom, I wasn't born yesterday, I will take a shower when I feel its appropriate, besides, i have this paper to finish writing for tomorrow.
by Sexydimma January 18, 2013
Slang sarcastic term for when a person doesn’t know much but does know something.
You know, I wasn’t exactly born yesterday, I was born day before yesterday!
by Dr Bunnygirl May 21, 2021
A phrase meaning , please stop giving me advice, I know what I am doing.
Mother. Adrian go take a shower, then do your homework, not the other way round.

Adrian. Mother., I wasn't born yesterday, I will take a shower when I feel its appropriate.
by Sexydimma January 11, 2013