You said it! INFORMAL
used to say that you agree with what has just been said:
"How stupid of me to lend him that money!" "You said it!"

[TahlilGaran] Advanced Learner's Dictionary ▲

you said it
I agree with you completely.
You said it, Mac, she really is a terrific singer, and I worry that I won't be nearly as good.

[TahlilGaran] English Idioms Dictionary ▲

You said it!
• You said it!/You can say that again!
that's true, you're right (used to show strong agreement with what another person has said)
"You can say that again," I answered when the woman mentioned how hot it was out in the sun.

[TahlilGaran] English Idioms Dictionary ▲

you said it
interj., slang
■ Used to show strong agreement with what another person has said.
"That sure was a good show." "You said it!"
"It sure is hot!" "You can say that again!"
Compare: SAY A MOUTHFUL.

[TahlilGaran] English Idioms Dictionary ▲