Inward-turning evolutionist (6)
I believe the answer is:
darwin
'evolutionist' is the definition.
(I've seen this in another clue)
'inward-turning' is the wordplay.
'turning' indicates anagramming the letters.
'inward' with letters rearranged gives 'DARWIN'.
(Other definitions for darwin that I've seen before include "Australian port, capital of the Northern Territory" , "Charles . . . . . . who formulated the theory of evolution" , "Man of note" , "Australia's northernmost state capital" , "Originator of the theory of evolution" .)