english
1
general::
A person who cannot be duped or taken advantage of, as in You can't put anything over on Ryan? he's nobody's fool. [Early 1900s]
American Heritage Idioms
2
general::
Phrase(s): nobody’s fool Fig. a sensible and wise person who is not easily deceived. • Mary is nobody’s fool. She watches out for people who might try to cheat her. • Anne may seem as though she’s not very bright, but she’s nobody’s fool.
McGrawhill's American Idioms And Phrasal Verbs