badly decayed and no longer good to use:
the smell of rotten eggs
Some of the wood was completely rotten.
The apples went rotten very quickly.
very bad [= terrible]:
What rotten luck!
a rotten idea
The service was rotten.
He's a rotten driver.
if someone is rotten, they are unpleasant, unkind, or dishonest:
Why are you being so rotten?
a rotten little brat
to feel ill
to feel unhappy and guilty about something:
I felt rotten about lying to him.
5 [only before noun] spoken
used when you are angry:
I don't want your rotten money!
The whole government is rotten to the core.
one bad person who has a bad effect on all the others in a group
—rottenness noun [uncountable]