(skrub) v. scrubbed, scrub·bing v.t
1. To rub vigorously, as with the hand or a brush, in washing.
2. To remove (dirt, etc.) by such action.
3. To cleanse (a gas).
—v.i.
4. To rub something vigorously in washing. See synonyms under CLEANSE.
—noun The act of scrubbing. [? <Scand. Cf. Dan. skrubbe.]

(skrub) noun
1. A stunted tree.
2. A thicket or tract of stunted trees or shrubs.
3. A domestic animal of inferior or impure breed.
4. A poor, insignificant person.
5. In sports, a player not on the varsity or regular team.
6. A game of baseball contrived hastily by a few players.
—adjective
1. Undersized or stunted–looking; inferior.
2. Consisting of or participated in by untrained players or scrubs: scrub team; scrub game. [Dial. var. of SHRUB¹]