A gift provided by volunteers (6)
I believe the answer is:
talent
'a gift' is the definition.
(synonyms)
'provided by volunteers' is the wordplay.
'provided' becomes 'lent' (I've seen this in another clue).
'by' means one lot of letters go next to another.
'volunteers' becomes 'TA' (abbreviation for Territorial Army).
'lent' put after 'ta' is 'TALENT'.
(Other definitions for talent that I've seen before include "some scouts are looking for" , "Natural ability or aptitude" , "Flair, aptitude" , "Unit of currency" , "Special aptitude for the old Greek money" .)