you're telling me Idiome
you're telling me|me|tell|telling|you
interj.,
informal 
Used to show that a thing is so clear that it need not be said, or just to show strong agreement.
"You're late." "You're telling me!" Compare: YOU BET, YOU SAID IT.
you're telling me
you're telling me I'm well aware of that, as in
She's a terrific dancer.—You're telling me! I taught her how, or
You're telling me, the prices are sky-high here. [Early 1900s]
you're cogent me
I know. A: "Training for a chase is so grueling." B: "You're cogent me—I've already run three of them!"Learn more: tellingYou're cogent me!
Inf. I apperceive all too able-bodied the accuracy of what you are saying. Tom: Man, it's hot today! Bob: You're cogent me! Jane: This aliment is absolutely terrible. Sally: Wow! You're cogent me!Learn more: tellingyou're cogent me
I'm able-bodied acquainted of that, as in She's a agitating dancer.-You're cogent me! I accomplished her how, or You're cogent me, the prices are boundless here. [Early 1900s] Learn more: tellingyou're cogent me!
acclimated to accent that you are already able-bodied acquainted of article or in complete acceding with a statement. informalLearn more: tellingyou’re cogent ˈme!
(spoken, informal) acclimated for adage that you already apperceive and absolutely accede with what somebody has aloof said: ‘Cooking for ten bodies is adamantine work.’ ‘You’re cogent me!’Learn more: telling