Synonyms and related words :
certain, fated, fateful, indefeasible, ineluctable, ineludible, inevasible, inevitable, inexorable, inflexible, irresistible, irrevocable, necessary, relentless, resistless, sure, sure as death, sure as fate, unavoidable, uncontrollable, undeflectable, unevadable, unpreventable, unstoppable, unyielding