Behoove is a verb used with an object. It means to be essential or dutiful. The formal construction is it behooves (someone) to do (something). However, most often the word is misused to mean the action benefits or gives gain to a person. Because this misuse is so prevalent, at least one dictionary we referenced has added advantageous as an alternative definition.
The formal negative formation is ill behoove. Again, the informal use is much more common and is does not behoove.
Outside the United States, behoove is spelled with one o.
Interestingly, behoof comes from the same Old English behōf or profit. It is a noun which means an benefit or gain. The mind jumps to this being the reason for the misuse of behoove, but there is no evidence that is the case.