Source : Webster's Revised Unabridged Dictionary (1913)

Fruitful \Fruit"ful\, a.
   Full of fruit; producing fruit abundantly; bearing results;
   prolific; fertile; liberal; bountiful; as, a fruitful tree,
   or season, or soil; a fruitful wife. -- {Fruit"ful*ly}, adv.
   -- {Fruit"ful*ness}, n.

         Be fruitful and multiply and replenish the earth.
                                                  --Gen. i. 28.

         [Nature] By disburdening grows More fruitful. --Milton.

         The great fruitfulness of the poet's fancy. --Addison.

   Syn: Fertile; prolific; productive; fecund; plentiful; rich;
        abundant; plenteous. See {Fertile}.

Source : WordNet®

fruitfulness
     n 1: the quality of something that causes or assists healthy
          growth [syn: {fecundity}] [ant: {fruitlessness}]
     2: the intellectual fruitfulness of a creative imagination
        [syn: {fecundity}]