Absurdity is fine in June, first and last (4)
I believe the answer is:
joke
'absurdity' is the definition.
(thesaurus)
'fine in june first and last' is the wordplay.
'fine' becomes 'ok' (synonyms).
'in' means one lot of letters goes inside another.
'first and last' means to remove the middle letters (only the first and last letters are used).
'june' with its centre taken out is 'je'.
'ok' put within 'je' is 'JOKE'.
'is' acts as a link.
(Other definitions for joke that I've seen before include "someone inadequate" , "something in cracker" , "Wisecrack" , "Quip, jest" , "Quip, witticism" .)