Turning out to be a real complex (9)
I believe the answer is:
elaborate
'complex' is the definition.
(thesaurus)
'turning out to be a real' is the wordplay.
'turning out' indicates an anagram.
'to'+'be'+'a'+'real'='tobeareal'
'tobeareal' anagrammed gives 'ELABORATE'.
(Other definitions for elaborate that I've seen before include "With many parts or details, maybe a pattern" , "involved" , "with added detail" , "Highly detailed" , "Add details to clarify meaning" .)