be as honest as the daybe as honest as the day (is long)
to be completely honest.
You can be as honest as the day is long and still get into trouble if you fill in your tax form incorrectly.
(redirected from be as honest as the day)
be as honest as the day is long
To be very truthful and reliable. Tom is as honest as the day is long—if he promised to help you move, then he'll be here.Kate would never cheat on an exam—she's as honest as the day is long.