Stop copper and solicitor (3,3)
I believe the answer is:
cut out
'stop' is the definition.
(cutting out is a kind of stopping)
'copper and solicitor' is the wordplay.
'copper' becomes 'Cu' (chemical symbol).
'and' says to put letters next to each other.
'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" .)