not counterfeit or copied; "an authentic signature"; "a bona fide manuscript"; "an unquestionable antique"; "photographs taken in a veritable bull ring"
conforming to fact and therefore worthy of belief; "an authentic account by an eyewitness"; "reliable information"
moving from one place to another and back again; "he traveled back and forth between Los Angeles and New York"; "the treetops whipped to and fro in a frightening manner"; "the old man just sat on the porch and rocked back and forth all day"