Clammy part in sprained ankle (4)
I believe the answer is:
dank
'clammy' is the definition.
(I know that clammy can be written as dank)
'part in sprained ankle' is the wordplay.
'part in' says the answer is hidden in the clue.
'DANK' can be found hidden inside 'sprained ankle'.
(Other definitions for dank that I've seen before include "Damp, cold, musty" , "(Of atmosphere) wet and unpleasant" , "Cold and moist" , "Clammy, damp" , "Unpleasantly cool and humid" .)