Verb
(idiomatic) To attack someone with great force.
At dawn we really let 'em have it with a 30 minute artillery barrage.
(idiomatic) To verbally assail someone.
When I came home, he let me have it for wrecking the car.
Used other than figuratively or idiomatically: see let, have, it.
When he showed me that he'd gotten the insurance certificate for our old car, I decided to let him have it.