When we say "am wise to someone," it means we are aware of their true intentions or we see through their facade. There are many synonyms to express this in different ways. For example, we may say "I am onto someone," "I am hip to their game," or "I am wise to their tricks." Other possible synonyms include "I see through their deception," "I know what they're up to," or "I'm not fooled by them." All of these phrases convey a sense of suspicion and perception, suggesting that the speaker is not easily taken in by someone's words or actions.