Synonyms of ruinous

1 Syllable
dire
2 Syllables
shabby, wrackful, fatal, wreckful, scrubby, harmful, crippling, noxious, tatty, scrubbier, shabbier, nocent, potest, damning, poter, fallen, deadly, tragic, hurtful, curer, draining
3 Syllables
pernicious, sanguineous, slaughterous, baleful, murderous, injurious, damaging, withering, exhausting, fateful, pound-foolish, pestilent, hellfire, baneful, suicidal, miasmatic, depleting, shattering, wasteful, disastrous
4 Syllables
lethiferous, cataclysmic, cataclysmal, deleterious, extravagant, destructive, calamitous, catastrophal, prejudicious, catastrophic, damnatory, subversive
5 Syllables
extirpative, unconducive, infelicitous, immoderate, impoverishing, dissipative, overgenerous, fire-and-brimstone, unfortunate
6 Syllables
annihilative, eradicative