'Gainful' definitions:

Definition of 'gainful'

From: WordNet
adjective
Yielding a fair profit [syn: gainful, paid, paying]

Definition of 'Gainful'

From: GCIDE
  • Gainful \Gain"ful\, a. Profitable; advantageous; lucrative. "A gainful speculation." --Macaulay. -- {Gain"ful*ly}, adv. -- {Gain"ful*ness}, n. [1913 Webster]