Synonyms for Unprofitable (same or very similar meaning)
WordNet sense 1 (not worth using):
inutileWordNet sense 2 (having no beneficial use or incapable of functioning usefully):
uselessWordNet sense 3 (without profit or reward):
profitlessWordNet sense 4 (not rewarding; not providing personal satisfaction):
unrewardingWordNet sense 5 (not yielding a return):
idleFrom the ODE community, based on WordNetadd/edit