Cartoonist maybe up for prize (6)
I believe the answer is:
reward
'for prize' is the definition.
(a prize may be given as a reward)
'cartoonist maybe up' is the wordplay.
'cartoonist maybe' becomes 'drawer' (someone who draws).
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'drawer' written backwards gives 'REWARD'.
(Other definitions for reward that I've seen before include "Present given to mark service or good deed" , "Recompense, remunerate" , "Desert" , "payment that's merited" , "Drawer (anag.)" .)