Relieve from — free (3)
I believe the answer is:
rid
I believe this clue is a double definition.
'relieve from' is the first definition.
(I've seen this before)
'free' is the second definition.
(to be free of something is to be rid of it)
(Other definitions for rid that I've seen before include "Clear, remove" , "Free, deliver, clear" , "Free, disencumber" , "Free from something unpleasant" , "Free (person of affliction)" .)