Debauched woman's son, say, with a small truck (9)
I believe the answer is:
dissolute
'debauched' is the definition.
(I know that debauched can be written as dissolute)
'woman's son say with a small truck' is the wordplay.
'woman's' becomes 'di's' (Di is short for Diana).
'son say' becomes 'sol' (I can't justify this - if you can you should give a lot more credence to this answer).
'with' is a charade indicator (letters next to each other).
'a small truck' becomes 'ute' (Australian abbreviation for utility vehicle; 'small' asks for an abbreviation).
'dis'+'sol'+'ute'='DISSOLUTE'
Can you help me to learn more?
(Other definitions for dissolute that I've seen before include "O, lust dies when one is this loose in morals" , "Sensually overindugent" , "Duelist so (anag) - debauched" , "Sensually overindulgent" , "Old tissue (anag) - like a rake?" .)