Second of April every year, that’s fine (6)
I believe the answer is:
peachy
'fine' is the definition.
(thesaurus)
'second of april every year' is the wordplay.
'second of april' becomes 'p' (2nd letter of 'april').
'every' becomes 'each' (synonyms).
'year' becomes 'y'.
'p'+'each'+'y'='PEACHY'
'that's' is the link.
(Other definitions for peachy that I've seen before include "Delicious" , "excellent!" .)