Source : Webster's Revised Unabridged Dictionary (1913)

Unfruitful \Un*fruit"ful\, a.
   Not producing fruit or offspring; unproductive; infertile;
   barren; sterile; as, an unfruitful tree or animal; unfruitful
   soil; an unfruitful life or effort. -- {Un*fruit"ful*ly},
   adv. -- {Un*fruit"ful*ness}, n.

Source : WordNet®

unfruitful
     adj : not fruitful; not conducive to abundant production [ant: {fruitful}]