The right I had to be free (3)
I believe the answer is:
rid
'be free' is the definition.
(to be free of something is to be rid of it)
'the right i had' is the wordplay.
'the right' becomes 'r' (common abbreviation).
'i had' becomes 'i'd' (contraction).
'r'+'id'='RID'
'to' acts as a link.
(Other definitions for rid that I've seen before include "Free, deliver, clear" , "Free, relieve" , "Clear, remove" , "Free (person of affliction)" , "Free, disencumber" .)