Read the dictionary definition of overbid. All definitions for this word.
1. (bridge) a bid that is higher than your opponent's bid (especially when your partner has not bid at all and your bid exceeds the value of your hand)
2. a bid that is higher than preceding bids
3. bid more than the object is worth
4. to bid for more tricks than one can expect to win,
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Merriam-Webster definition of overbid