Definition of scrub:
"How solitary, how scrub, does this town look!" -Walpole.
one who labors hard and lives meanly; a mean fellow; one who is a freak or unable to complete easy tasks
"we should go there in as proper a manner possible; nor altogether like the scrubs about us."
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; to rub anything hard, especially with a wet brush; to scour;
"engineers had to scrub the satellite launch due to bad weather."