Disencumber (3)
I believe the answer is:
rid
'disencumber' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for rid that I've seen before include "Free (person of affliction)" , "Free, relieve" , "Free (someone of something unwanted)" , "Throw off, unburden" , "Free, disencumber" .)