Irritating supporters -- one in street (8)
I believe the answer is:
abrasive
'irritating' is the definition.
(I've seen this before)
'supporters one in street' is the wordplay.
'supporters' becomes 'bras' (a bra gives support to breasts).
'one' becomes 'I' (Roman numeral).
'in' means one lot of letters goes inside another.
'street' becomes 'ave' (abbreviation for Avenue).
'bras'+'i'='brasi'
'brasi' inserted within 'ave' is 'ABRASIVE'.
(Other definitions for abrasive that I've seen before include "Harsh - chafing" , "Emery paper or steel wool, say" , "Caustic, harsh" , "Causing irritation" , "smooth? The opposite" .)