Definition of wasn't born yesterday
- He said he'd pay me back, but I'll believe it when I see it. I wasn't born yesterday.
: was not
: on the day last past : on the day preceding today
: at a time not long past : only a short time ago
: the day last past : the day next before the present
: recent time : time not long past
: past time
What made you want to look up wasn't born yesterday? Please tell us where you read or heard it (including the quote, if possible).