Turning out lions' compound (8)
I believe the answer is:
solution
'compound' is the definition.
(thesaurus)
'turning out lions'' is the wordplay.
'turning' indicates anagramming the letters.
'out'+'lions'='outlions'
'outlions' with letters rearranged gives 'SOLUTION'.
(Other definitions for solution that I've seen before include "compound" , "Way out" , "Answer (to a puzzle)" , "Elucidation - mixture of substances" , "Puzzle's answer" .)