Good state channel (6)
I believe the answer is:
gutter
'channel' is the definition.
(gutter is a kind of channel)
'good state' is the wordplay.
'good' becomes 'g' (abbreviation).
'state' becomes 'utter' (I've seen this before**).
'g'+'utter'='GUTTER'
(Other definitions for gutter that I've seen before include "Someone removing contents" , "Drainage trough" , "dirty channel?" , "Rain channel; (flame) start to die" , "Threaten to go out" .)