know better

Verb

 * 1)  To recognize that a statement or belief is false or doubtful.
 * 2)  To understand that certain behavior is wrongful, futile, or inappropriate.
 * 1)  To understand that certain behavior is wrongful, futile, or inappropriate.
 * 1)  To understand that certain behavior is wrongful, futile, or inappropriate.

Usage notes

 * Sometimes used without further explication and sometimes used with followed by a description of the belief or behavior, as in "He knows better than to take what does not belong to him".
 * Know better has a much higher tendency to be used in the positive (example: "he knows better") than its synonym, know any better (example: "he didn't know any better").