Available Definitions:
1) v. t. - To rub hard; to wash with rubbing; usually, to rub with a wet brush, or with something coarse or rough, for the purpose of cleaning or brightening; as, to scrub a floor, a doorplate.
2) v. i. - To rub anything hard, especially with a wet brush; to scour; hence, to be diligent and penurious; as, to scrub hard for a living.
3) n. - One who labors hard and lives meanly; a mean fellow.
4) n. - Something small and mean.
5) n. - A worn-out brush.
6) n. - A thicket or jungle, often specified by the name of the prevailing plant; as, oak scrub, palmetto scrub, etc.
7) n. - One of the common live stock of a region of no particular breed or not of pure breed, esp. when inferior in size, etc.
8) a. - Mean; dirty; contemptible; scrubby.