A person who is extremely well-versed in all things related to Marijuana. Usually a dealer or grower himself, a Kushmaster knows how to roll the best joints, pack the most righteous bowls, and he always has a lighter. Kushmasters usually smoke a quad a day or more, and they will be down to bake anytime, anywhere.
Person: Hey Kushmaster Dave, how much for an eighth?
Kushmaster Dave: Sorry man, I only deal in pounds. But have some of this Skywalker OG, its dank as hell (passes J).