Cool floppy sunhat with nice suit (14)
I believe the answer is:
unenthusiastic
'cool' is the definition.
(I've seen this before)
'floppy sunhat with nice suit' is the wordplay.
'floppy' indicates an anagram.
'with' is a charade indicator (letters next to each other).
'nice'+'suit'='nicesuit'
'sunhat' after 'nicesuit' is 'nicesuitsunhat'.
'nicesuitsunhat' with letters rearranged gives 'UNENTHUSIASTIC'.
(Other definitions for unenthusiastic that I've seen before include "like a fan? No" , "apathetic" , "Showing no interest" , "Not keen" , "Cool" .)