the ability to say things that are clever and amusing:
a woman of great wit and charm
quick/dry/sharp etc wit
His sharp wit had them all smiling.
someone who is able to say clever and amusing things
your ability to think quickly and make the right decisions:
Alone and penniless, I was forced to live on my wits.
keep/have your wits about you (=be ready to think quickly and do what is necessary in a difficult situation)
to frighten someone very much:
I was terrified out of my wits at the very idea.
to make yourself think about what you are going to do next after you have been surprised by something:
I felt helpless, but tried to gather my wits.
to compete against someone in a test of knowledge or intelligence
to be very upset and not know what to do, because you have tried everything possible to solve a problem
to be clever enough to know the right thing to do:
Thankfully, Reid had the wit to see what was wrong with the plan.
not be too difficult for someone to do:
It's surely not beyond the wit of man to come up with a solution.
10 old use or formal
used to introduce additional information which makes it clear exactly who or what you are talking about [= namely]:
This does not stop me giving you a little treat. To wit, an invitation to dine at Brown's.