Answer line given in delicate last act (6)
I believe the answer is:
finale
'last act' is the definition.
(I've seen this in another clue)
'answer line given in delicate' is the wordplay.
'answer' becomes 'a' (abbreviation eg in Q and A).
'line' becomes 'l' (used when specifying particular lines from a poem).
'given in' is an insertion indicator.
'delicate' becomes 'fine' (synonyms).
'a'+'l'='al'
'al' going within 'fine' is 'FINALE'.
(Other definitions for finale that I've seen before include "Climax, end" , "Conclusion of a performance" , "In leaf (anag.)" , "When it's grand, it's the last scene" , "Closing part of an entertainment" .)