From Longman Dictionary of Contemporary Englishbarkerbark‧er /ˈbɑːkə $ ˈbɑːrkər/ noun [countable] BODLOin the past, someone who stood outside a place where there was a circus or fair, shouting to people to come in
Examples from the Corpus
barker• Movies were announced to the world by electric signs, posters, music, and barkers.• Spent three days as roustabout and barker with the jerry Lepke Ten-in-One Carnival.• Boyle has always liked to play circus barker for life's extremes, and what better freak show than the environmental apocalypse?• There had always been something of the fairground barker about Mr Broadhurst and during this period he enhanced it.• McMurphy drew eyes to him like a sideshow barker. 