causing great distress or injury; ruinous; very unfortunate; calamitous

The rain and cold proved disastrous to his health.

Archaic . foreboding disaster.

adjective

blessed , fortunate , lucky , miraculous , prosperous , successful , triumphant , winning , wondrous

adjective

adverse , calamitous , cataclysmal , cataclysmic , catastrophic , destructive , dire , dreadful , fatal , fateful , hapless , harmful , ill-fated , ill-starred , luckless , ruinous , terrible , tragic , unfavorable , unfortunate , unlucky , unpropitious , untoward , deplorable , devastating , horrendous , ill-fate