Prosper and show off (8)
I believe the answer is:
flourish
This clue is a double definition.
'prosper' is the first definition.
(I know that prosper can be written as flourish)
'show off' is the second definition.
(I've seen this before)
'and' is the link.
(Other definitions for flourish that I've seen before include "success" , "Fine food is hard to" , "Large vase, pot" , "show off" , "Showy gesture" .)