Sentence:  Like most human activities, ballooning has sponsored heroes and hucksters and a good deal in between. For every dedicated scientist patiently recording atmospheric pressure and wind speed while shivering at high altitudes, there is a carnival <WSD>barker</WSD> with a bevy of pretty girls willing to dangle from a basket or parachute down to earth. 
Meaning of the word marked with <WSD> tags:  A person employed to solicit customers by calling out to passersby, e.g. at a carnival.