What's embraced by the don is mindless pursuit of pleasure (8)
I believe the answer is:
hedonism
'pursuit of pleasure' is the definition.
(I've seen this before)
'what's embraced by the don is mindless' is the wordplay.
'what's embraced' says the answer is hidden in the clue.
'HEDONISM' is hidden within 'by the don is mindless'.
(Other definitions for hedonism that I've seen before include "System based on pleasure as the highest good" , "Living for pleasure" , "His demon (anag.)" , "Search for fun" , "The pusuit of pleasure as life's greatest good" .)