take for an idiot and take for a fool

take (one) for a fool

To presume or believe that one is very stupid or foolish. I'd advise you not to take her for a fool. She may play dumb, but she's very crafty.
See also: fool, take

take (one) for an idiot

To presume or believe that one is very stupid or foolish. I'd advise you not to take her for an idiot. She may play dumb, but she's very crafty. Do you take me for an idiot? There's no way I'm falling for that again.
See also: idiot, take

take someone for an idiot and take someone for a fool

to assume that someone is stupid. I wouldn't do anything like that! Do you take me for an idiot? I don't take you for a fool. I think you're very clever.
See also: and, fool, idiot, take