IPA: /ˈbrɒŋ.kəˌbʌs.tər/
KK: /ˈbrɒŋkəˌbʌstər/
A person who trains wild horses to be ridden by breaking them in.
The broncobuster skillfully tamed the wild horse during the rodeo.
Broncobuster is formed from "bronco" (from Spanish "bronco", meaning rough or wild) and "buster" (from the verb "bust", meaning to break or burst). The term refers to someone who breaks or tames a wild horse.
Imagine a person who 'breaks' ('buster') a 'wild horse' ('bronco') — that's what a broncobuster does.
No commonly confused words.