Less-than-serious flight for fun, not entirely dreadful (8)
I believe the answer is:
flippant
'dreadful' is the definition.
Both the definition and answer are adjectives. Perhaps there's an association between them I don't understand?
'less-than-serious flight for fun not entirely' is the wordplay.
I cannot quite see how this works, but
'not' could be 'nt' (synonyms) and 'nt' is located in the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for flippant that I've seen before include "Showing disrespectful levity" , "light" , "Cheeky" , "Impudent" , "Irreverent, saucy" .)