Gift of new tunic to Robin (12)
I believe the answer is:
contribution
'gift' is the definition.
(contribution is a kind of gift)
'new tunic to robin' is the wordplay.
'new' indicates an anagram.
'tunic'+'to'+'robin'='tunictorobin'
'tunictorobin' is an anagram of 'CONTRIBUTION'.
'of' acts as a link.
(Other definitions for contribution that I've seen before include "given financial assistance" , "Gift" , "Something given towards a common purpose" , "Input" , "Something given towards a common aim" .)