Irritating when I've to restrain supporter (8)
I believe the answer is:
abrasive
'irritating' is the definition.
(I've seen this before)
'when i've to restrain supporter' is the wordplay.
'when' becomes 'as' (eg 'when I walked' means 'as I walked').
'to restrain' is an insertion indicator.
'supporter' becomes 'bra' (a bra gives support to breasts).
'as'+'ive'='asive'
'asive' placed around 'bra' is 'ABRASIVE'.
(Other definitions for abrasive that I've seen before include "Harsh - scratchy" , "Harsh - chafing" , "rubbing" , "Causing irritation" , "Arabs vie to be harsh or provocative" .)