1
general::
Phrase(s): I’m with you.
I agree with you.; I will join with you in doing what you suggest. (With a stress on both I and you.) • Sally: I think this old bridge is sort of dangerous. Jane: I’m with you. Let’s go back another way. • Bob: This restaurant looks horrible. Bill: I’m with you. Want to go somewhere else?
McGrawhill's American Idioms And Phrasal Verbs