I (OR SHE, ETC.) WASN'T BORN YESTERDAY


Meaning of I (OR SHE, ETC.) WASN'T BORN YESTERDAY in English

I ( or she, etc.) wasn't born yesterday

I am (or she, etc. is) not foolish or gullible.

→ born

Concise Oxford English vocab.      Сжатый оксфордский словарь английского языка.