Superficial fool with virus flounders (9)
I believe the answer is:
frivolous
'superficial' is the definition.
(associated in meaning)
'fool with virus flounders' is the wordplay.
'with' says to put letters next to each other.
'flounders' indicates anagramming the letters (I've seen 'flounder' mean this).
'fool' after 'virus' is 'virusfool'.
'virusfool' is an anagram of 'FRIVOLOUS'.
(Other definitions for frivolous that I've seen before include "Trifling, silly" , "Unserious" , "Trivial - flippant" , "Carefree and not serious" , "Carefree, superficial" .)