rub
     n 1: an unforeseen obstacle [syn: {hang-up}, {hitch}, {snag}]
     2: the act of rubbing or wiping; "he gave the hood a quick rub"
        [syn: {wipe}]
     v 1: move over something with pressure; "rub my hands"; "rub oil
          into her skin"
     2: cause friction; "my sweater scratches" [syn: {fray}, {fret},
         {chafe}, {scratch}]
     3: scrape or rub as if to relieve itching; "Don't scratch your
        insect bites!" [syn: {scratch}, {itch}]
     [also: {rubbing}, {rubbed}]
Source: WordNet® 2.0