Productive (8)
'productive' is the definition.
(similar in meaning)
This is the entire clue.
(Other definitions for fruitful that I've seen before include "rich" , "Fertile, abundant" , "Fertile, productive" , "Rewarding" , "Prolific in bearing offspring" .)
'productive' is the definition.
(thesaurus)
This is the entire clue.
(Other definitions for useful that I've seen before include "Make yourself . . . . . . - help out" , "Of service" , "Utilitarian" , "Advantageous; very able" , "Of practical assistance" .)