Opposed to cooker in street (7)
I believe the answer is:
against
'opposed to' is the definition.
(I've seen this before)
'cooker in street' is the wordplay.
'cooker' becomes 'aga' (I've seen this before).
'street' becomes 'st' (abbreviation).
'aga'+'in'+'st'='AGAINST'
(Other definitions for against that I've seen before include "In conflict with" , "In disagreement with" , "In opposition to" , "In competition with" , "In contrast to; touching" .)