Chills out after a tough day (7)
I believe the answer is:
unwinds
'chills out after a tough day' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for unwinds that I've seen before include "Relaxes; pays out (thread)" , "Rests and becomes less tense" , "Becomes less tense and relaxes" .)