Sign of a sprained ankle (4)
I believe the answer is:
limp
'sign of a sprained ankle' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for limp that I've seen before include "Walk with difficulty" , "Lacking stiffness" , "Slack, wilted" , "Walk with uneven gait" , "Saggy and drooping" .)