Synonyms and related words :
certainty, fate, fatefulness, force majeure, indefeasibility, ineluctability, inescapableness, inevasibleness, inevitability, inevitable accident, inevitableness, inexorability, inflexibility, irrevocability, necessity, predetermination, relentlessness, sureness, unavoidable casualty, unavoidableness, uncontrollability, undeflectability, unpreventability, unyieldingness, vis major