Stop scratching head for relaxation (4)
I believe the answer is:
ease
'relaxation' is the definition.
('ease' can be a synonym of 'relaxation')
'stop scratching head' is the wordplay.
'stop' becomes 'cease' (I've seen this before).
'scratching head' means to remove the first letter.
'cease' with its first letter removed is 'EASE'.
'for' is the link.
(Other definitions for ease that I've seen before include "Comfort; facility" , "Relieve or slacken" , "At this, one is relaxed" , "Rest and leisure" , "Poise or leisure" .)