Synonyms of devastating

2 Syllables
telling, lethal, stunning
3 Syllables
pernicious, sanguineous, slaughterous, murderous, necrotic, mortifying, miasmatic, disastrous
4 Syllables
consumptive, cataclysmal, destructive, calamitous, catastrophal, desolating, overwhelming
5 Syllables
annihilating