Loud article on small groupies (4)
I believe the answer is:
fans
'groupies' is the definition.
(I've seen this in another clue)
'loud article on small' is the wordplay.
'loud' becomes 'f' (short for forte - 'loud' in music).
'article' becomes 'an' (indefinite article).
'on' is a charade indicator (letters next to each other).
'small' becomes 's' (abbreviation - e.g. clothes size).
'f'+'an'+'s'='FANS'
(Other definitions for fans that I've seen before include "Admirers" , "Devices for creating currents of air" , "Enthusiasts" , "Provokes" , "Supporters" .)