underbid vs overbid

underbid is not a noun while overbid is a noun.

Word	Noun	Adjective	Verb	Adverb
underbid	No	No	Yes	No
overbid	Yes	No	Yes	No

underbid (noun)	overbid (noun)
	a bid that is higher than preceding bids
	(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)

underbid (verb)	overbid (verb)
bid too low	bid more than the object is worth
bid lower than a competing bidder	to bid for more tricks than one can expect to win
bid (a hand of cards) at less than the strength of the hand warrants