I am willing to give it back (3)
I believe the answer is:
ago
'back' is the definition.
('years back' means 'years ago')
'i am willing to give it' is the wordplay.
I cannot really see how this works, but
'i' could be 'a' and 'a' is present in the answer.
'give' could be 'go' (synonyms) and 'go' is present in the answer.
No letters remain.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for ago that I've seen before include "Gone, past, since" , "Time past" , "Previously" , "Back (in time)" , "Earlier, gone by" .)