The definition of snide is someone or something rude, snobby, mocking, devious or underhanded.(adjective)
See snide in Webster's New World College Dictionary
Origin: orig., counterfeit, bogus < thieves' slang, prob. of Du dial. or Ger orig. < base of Ger schneiden, to cut, with reference to coin clipping and, later, to cutting remarks
See snide in American Heritage Dictionary 4
adjective snid·er, snid·est
Origin: Origin unknown.
Learn more about snide