Watch salesman with consumer (8)
I believe the answer is:
repeater
'watch' is the definition.
(thesaurus)
'salesman with consumer' is the wordplay.
'salesman' becomes 'rep' (I've seen this before).
'with' is a charade indicator (letters next to each other).
'consumer' becomes 'eater' (eater is a kind of consumer).
'rep'+'eater'='REPEATER'
(Other definitions for repeater that I've seen before include "Timepiece that strikes the hours" , "Type of clock or firearm" , "Handgun able to fire again without reloading" , "One keeps saying" , "Amplifier in phone line" .)