Show-off with scholarship is last in sport (13)
I believe the answer is:
exhibitionist
'show-off' is the definition.
(someone who shows off)
'scholarship is last in sport' is the wordplay.
'scholarship' becomes 'exhibition' (I've seen this before).
'last in' suggests the final letters.
The last letter of 'sport' is 't'.
'exhibition'+'is'+'t'='EXHIBITIONIST'
'with' is the link.
(Other definitions for exhibitionist that I've seen before include "Show-off" , "Attention-seeker" , "Flasher?" .)