n One who labors hard and lives meanly; a mean fellow.
n One who is a freak or unable to complete easy tasks.
n A thicket or jungle, often specified by the name of the prevailing plant; as, oak 'scrub', palmetto 'scrub', etc.
n (US|stock breeding) One of the common livestock of a region of no particular breed or not of pure breed, especially when inferior in size, etc. Often used to refer to male animals unsuited for breeding.
n Vegetation of inferior quality, though sometimes thick and impenetrable, growing in poor soil or in sand; also, brush.
n One not on the first team of players, a substitute.
v (transitive) 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.
v (intransitive) To rub anything hard, especially with a wet brush; to scour;
v (intransitive|figuratively) To be diligent and penurious; as, to 'scrub' hard for a living.
v (transitive) To call off a scheduled event; to cancel.
v (databases|transitive) To eliminate or to correct data from a set of records to bring it inline with other similar datasets
v (context|audio) To move a recording tape back and forth with a scrubbing-like motion to produce a scratching sound, or to do so by a similar use of a control on an editing system.
v (context|audio|video) To maneuver the play position on a media editing system by using a scroll bar.