Turned up, say, obscure insect (5)
I believe the answer is:
midge
'insect' is the definition.
(midge is a kind of insect)
'turned up say obscure' is the wordplay.
'turned up' says the letters should be written backwards.
'say' becomes 'eg'.
'obscure' becomes 'dim' (I've seen this before).
'eg'+'dim'='egdim'
'egdim' back-to-front is 'MIDGE'.
(Other definitions for midge that I've seen before include "Tiny swarming insect" , "Be an obstacle" , "Small flying insect" , "Gnat" , "Dipterous insect, in swarms by water" .)