Apply again (5)
I believe the answer is:
reuse
'apply again' is the definition.
('use' can be a synonym for 'apply' so perhaps 'reuse' is OK for 'apply again')
This is all the clue.
(Other definitions for reuse that I've seen before include "Recycle (something)" , "For another time enjoy" , "The aim of recycling" , "Employ again" .)