From Longman Dictionary of Contemporary Englishlet somebody have itlet somebody have itinformal to attack someone → let
Examples from the Corpus
let somebody have it• As for the Cub players they came out on the steps of their dugout and really let me have it.• He says that you just let them have it!• Instead of saying no, they let the kids have it.• They suggested she borrow the money until such time as they could let her have it.• We should have let them have it.• Netscape hooked millions of web surfers on Navigator by letting them have it for free.• Mrs. Kramer really let him have it for spilling the paint.• Do report recurring faults to the developers; that's why they let you have it free.• I let him have it to get rid of him. 