Enthusiasm after crossword answer and editor's cheerful (5-7)
I believe the answer is:
light-hearted
'cheerful' is the definition.
(both can mean jolly or carefree)
'enthusiasm after crossword answer and editor's' is the wordplay.
'enthusiasm' becomes 'heart' (I've seen this before).
'after' is a charade indicator (letters next to each other).
'crossword answer' becomes 'light' (spaces for answers in crosswords are called lights).
'and' is a charade indicator (letters next to each other).
'editor' becomes 'ed' (abbreviation).
'heart' after 'light' is 'lightheart'.
'lightheart'+'ed'='LIGHT-HEARTED'
(Other definitions for light-hearted that I've seen before include "Free from anxiety" , "Cheerful, carefree" , "Playful" , "Cheerful, unserious" , "Airy and carefree" .)