expression, godan verb (-u)
look who's talking; you're one to talk
Used to retort when someone criticizes or gives advice despite having the same fault or being in no position to do so. Often carries a sarcastic or indignant tone.
「遅刻するな」って、どの口が言うの？
You're telling me not to be late? Look who's talking!
いつもサボってるくせに、どの口が
You're always slacking off, so you're one to talk.