Well off for fun; left a surprise (8)
I believe the answer is:
affluent
'well off' is the definition.
(I've seen this before)
'fun left a surprise' is the wordplay.
'fun left a' can be anagrammed to 'AFFLUENT'.
But, I'm not sure how this is indicated.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for affluent that I've seen before include "comfortable" , "Well off, having plenty of money" , "Very well off, quite rich" , "Well-to-do, wealthy" , "Well-to-do, got lots of money" .)