A person who will get the job done by ANY means. A grubster is tough, mean, and determined. The first
time I heard the term, it was a nickname for a
football linebacker at my highschool. His name was Bing which didn't sound very tough so his team mates called him grubster. He would
hit guys so hard that the "pop" sound would echo through the stands. Twenty years later, everyone I know still uses the term. I even hear people I don't know use the term.