bullwhacker

[ boo l-hwak-er, -wak- ]
/ ˈbʊlˌʰwæk ər, -ˌwæk- /

noun Western U.S.

(especially in the early 19th century) the driver of a team of oxen.

Origin of bullwhacker

An Americanism dating back to 1855–60; bull1 + whacker