the.com/buster

means A person (or thing) that breaks, tames, or defeats something — a bronco buster subdues horses, a crime buster stops lawbreakers, a myth buster debunks falsehoods — and also a casual, slightly cocky way of addressing someone ('listen, buster').

from From 'bust,' a dialectal American variant of 'burst' that emerged in the early-to-mid 1800s, shifting the word from pure destruction toward taming, breaking in, or overpowering something (as in 'bust a bronco'). Tack on the agent suffix '-er' and you get 'buster': one who busts. The address-term use ('okay, buster') followed in American slang, carrying a tough, informal, faintly challenging edge — the verbal equivalent of rolling up your sleeves.