The Collaborative International Dictionary of English v.0.48:

Behoof \Be*hoof"\, n. [OE. to bihove for the use of, AS. beh?f
   advantage, a word implied in beh?fl[imac]c necessary; akin to
   Sw. behof, Dan. behov, G. behuf, and E. heave, the root
   meaning to seize, hence the meanings "to hold, make use of."
   See Heave, v. t.]
   Advantage; profit; benefit; interest; use.
   [1913 Webster]

         No mean recompense it brings
         To your behoof.                          --Milton.
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

21 Moby Thesaurus words for "behoof":
   advantage, avail, behalf, benefit, benison, blessing, boon,
   convenience, gain, good, interest, percentage, point, profit,
   service, use, value, welfare, well-being, world of good, worth



Bouvier's Law Dictionary, Revised 6th Ed (1856):

BEHOOF. As a word of discourse, Signifies need, (egestas, necessitas,
indigentia.) It comes from behoove, (Sax. behoven,) to need or have need of.
In a secondary sense, which is the law sense of the word, it signifies use,
service, profit, advantage, (interesse, opus.) It occurs in conveyances of
land in fee simple.