Setter perhaps twisted language (7)
I believe the answer is:
gelatin
'setter' is the definition.
(substance which sets or hardens)
'perhaps twisted language' is the wordplay.
'perhaps' becomes 'eg' (for example).
'twisted' is a reversal indicator.
'language' becomes 'latin' (Latin is an example).
'eg' back-to-front is 'ge'.
'ge'+'latin'='GELATIN'
(Other definitions for gelatin that I've seen before include "Colourless protein - edible jelly" , "Thickener" , "Setter" , "Tag line (anag.); glue" , "something gluey" .)