Pretentious type has no business taking part (4)
I believe the answer is:
snob
'pretentious type' is the definition.
(I've seen this in another clue)
'has no business taking part' is the wordplay.
'taking part' indicates the answer is hidden within the clue.
'SNOB' is hidden in the letters of 'has no business'.
(Other definitions for snob that I've seen before include "One attaching importance to social position" , "blackleg" , "High-minded type" , "One looks down on others" , "Prig" .)