What is the meaning of scrub?

noun

• Dense vegetation consisting of stunted trees or bushes.
  • synonyms: chaparral, bush
• The act of cleaning a surface by rubbing it with a brush and soap and water.
  • synonyms: scrubbing, scouring

verb

• Clean with hard rubbing.
  • usage: "She scrubbed his back"
  • synonyms: scour
• Wash thoroughly.
  • usage: "surgeons must scrub prior to an operation"
  • synonyms: scrub up
• Postpone indefinitely or annul something that was scheduled.
  • usage: "Call off the engagement"; "cancel the dinner party"; "we had to scrub our vacation plans"; "scratch that meeting-the chair is ill"
  • synonyms: cancel, call off, scratch

adjective

• Of domestic animals. ( not selectively bred).