Pa ceased to be prepared for adventure (8)
I believe the answer is:
escapade
'adventure' is the definition.
('escapade' can be a synonym of 'adventure')
'pa ceased to be prepared' is the wordplay.
'to be prepared' is an anagram indicator.
'pa'+'ceased'='paceased'
'paceased' is an anagram of 'ESCAPADE'.
'for' acts as a link.
(Other definitions for escapade that I've seen before include "Madcap adventure" , "Daring stunt" , "daring exploit" , "Daring adventure" , "quite a lark" .)