From Longman Dictionary of Contemporary Englishoverplay your handoverplay your handTRY TO DO OR GET somethingto behave too confidently because you think you are in a stronger position than you actually are The unions overplayed their hand in the end and failed to get the pay rise they wanted. → overplay
Examples from the Corpus
overplay your hand• By opposing even a moderate ban on assault weapons, the gun lobby has overplayed its hand.• Eventually, however, Safdarjung overplayed his hand.• Should she spell it out to him, or would that fatally overplay her hand?• This drove a much harder bargain and, it has been suggested, represents the moment at which Edward overplayed his hand.• The unions overplayed their hand in the end.• If his opponents were intent on overplaying their hand, it could only improve his position with the cardinal. 