Match of immense quality (5)
I believe the answer is:
equal
'match' is the definition.
(I know that match can be written as equal)
'of immense quality' is the wordplay.
'of' indicates a hidden word.
'EQUAL' is hidden within 'immense quality'.
(Other definitions for equal that I've seen before include "Identical, add up to" , "Be as good as, match" , "Peer; evenly balanced" , "Match, rival" , "Like revolting farm animals" .)