Stops head resigning and relaxes (5)
I believe the answer is:
eases
'relaxes' is the definition.
(I've seen this before)
'stops head resigning' is the wordplay.
'stops' becomes 'ceases' ('cease' can be a synonym of 'stop').
'head resigning' means to remove the first letter.
'ceases' with its initial letter taken off is 'EASES'.
'and' is the link.
(Other definitions for eases that I've seen before include "Makes less severe" , "Makes more comfortable" , "Lessens tensions" , "Calms" , "Alleviates, relieves" .)