A criminal flipped, ruddy willing! (8)
I believe the answer is:
prepared
'willing' is the definition.
(similar in meaning)
'a criminal flipped ruddy' is the wordplay.
'criminal' becomes 'perp' (I've seen this in another clue).
'flipped' shows that the letters should be reversed in order.
'ruddy' becomes 'red' (synonyms).
'a'+'perp'='aperp'
'aperp' written backwards gives 'prepa'.
'prepa'+'red'='PREPARED'
(Other definitions for prepared that I've seen before include "All set" , "Waiting" , "Ready for action" , "Made or got ready" , "edited" .)