play for a fool
play someone for a fool
Fig. to treat someone like a fool; to assume someone is naive or stupid. Don't play me for a fool. I won't have it. You are playing me for a fool! Stop it!
play somebody for a fool(American & Australian)
to treat someone as if they are stupid, especially by trying to get something from them in a way that is not fair He's playing you for a fool. Just don't lend him any more money.