What is the meaning of rub?

noun

• An unforeseen obstacle.
  • synonyms: hang-up, hitch, snag
• The act of rubbing or wiping.
  • usage: "he gave the hood a quick rub"
  • synonyms: wipe

verb

• Move over something with pressure.
  • usage: "rub my hands"; "rub oil into her skin"
• Cause friction.
  • usage: "my sweater scratches"
  • synonyms: fray, fret, chafe, scratch
• Scrape or rub as if to relieve itching.
  • usage: "Don't scratch your insect bites"
  • synonyms: scratch, itch