be wise to
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be wise to somebody/somethingalso get wise to somebody/something
to know about and not be fooled by someone or something He called in sick almost every Monday, and the boss quickly got wise to him.
Usage notes: often used in the forms wise up (to something/someone) or wise someone up (to something/someone): I finally wised up to their scheme. It's time they wised him up to what's really going on.
See also: wise