(idiomatic, intransitive) To be crazy or eccentric.

(US, humorous) Used to report that a (major) problem has occurred.

(slang, of a person) To be crazy.

A rhetorical question used to express incredulity or surprise: who would have guessed it?; who would have thought that would happen?

(idiomatic, colloquial) to exercise total control over someone.

(dated) To have the bumps, indentations, and shape of one's skull examined and interpreted by a phrenologist. / (idiomatic) To have one's mental health assessed, to receive a psychiatric examination.

(colloquial, medicine) To undergo a tubal ligation.

Alternative form of you could have fooled me

(New England, idiomatic, obsolete) To be drunk.

(colloquial) To be a sensible thinker capable of making sound decisions.