一点儿都不傻，不易受人愚弄（或欺骗）
to not be stupid or easily deceived
I notice Ed didn't offer to pay for her - he's no fool. 我发现埃德并没有提出要替她付账——他可一点儿都不傻。
She's no fool. She knows if she's nice to him, he'll pay for her holiday.
Of course Alex stays in touch with his wealthy old grandfather - he's nobody's fool.
I mean, he's no fool. Once he'd worked out he wasn't going to be promoted, he was off.
Lucy's really nice, but she's nobody's fool and she wouldn't put up with that sort of treatment.
See also: fool noun (PERSON)