Cooker in street, on (7)
I believe the answer is:
against
'on' is the definition.
(against can mean on or adjacent to)
'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 "Not supporting" , "In conflict with" , "Versus - in contact with" , "Anti, touching" , "In competition with" .)