rub

(noun) an unforeseen obstacle. Synonyms: hang-up, hitch, snag.

(noun) the act of rubbing or wiping. Synonyms: wipe. Examples: "He gave the hood a quick rub."

(verb) move over something with pressure. Examples: "Rub my hands." "Rub oil into her skin."

(verb) cause friction. Synonyms: fray, fret, chafe, scratch. Examples: "My sweater scratches."

(verb) scrape or rub as if to relieve itching. Synonyms: scratch, itch. Examples: "Don't scratch your insect bites!."