Stop copper and solicitor (3,3)
I believe the answer is:
cut out
'stop' is the definition.
(I know that cut out is a more specific form of stop)
'copper and solicitor' is the wordplay.
'copper' becomes 'Cu' (chemical symbol).
'and' means one lot of letters go next to another.
'solicitor' becomes 'tout' (someone who solicits business).
'cu'+'tout'='CUT-OUT'
(Other definitions for cut out that I've seen before include "Cease to function, like car engine" , "25 [FAIL]" , "Stop" , "Automatic safety circuit-breaker" , "Excise" .)