Unavoidable

1. (a.) Incapable of being prevented; inevitable; necessary; as, unavoidable troubles.

2. (a.) Not voidable; incapable of being made null or void.

Thesaurus Entries

certain, definite, destined, determined, fated, fateful, fixed, indefeasible, ineluctable, ineludible, inescapable, inevasible, inevitable, inexorable, inflexible, irresistible, irrevocable, necessary, predestined, predetermined, relentless, resistless, settled, sure, sure as death, sure as fate, unalterable, unchangeable, uncontrollable, undeflectable, unevadable, unpreventable, unstoppable, unyielding