The Collaborative International Dictionary of English v.0.48:

Fructuous \Fruc"tu*ous\, a. [L. fructuosus: cf, F. fructueux.]
   Fruitful; productive; profitable. [Obs.]
   [1913 Webster]

         Nothing fructuous or profitable.         --Chaucer.
   -- Fruc"tu*ous*ly, adv. -- Fruc"tu*ous*ness, n. [Obs.]
   [1913 Webster]

Moby Thesaurus II by Grady Ward, 1.0:

36 Moby Thesaurus words for "fructuous":
   advantageous, advisable, appropriate, becoming, befitting,
   congruous, convenient, decent, desirable, expedient, favorable,
   feasible, felicitous, fit, fitten, fitting, good, happy, likely,
   meet, opportune, politic, profitable, proper, recommendable, right,
   seasonable, seemly, sortable, suitable, timely, to be desired,
   useful, well-timed, wise, worthwhile