Synonyms of alarming

1 Syllable
dread
2 Syllables
dreader, troublous, parlous, scariest, scary, louring, startling, frightful, dreadful, scarier, awful, grabber, loury
3 Syllables
jeopardous, portentous, disturbing, distressing, lowery, frightening, harrowing, disquieting, perturbing, terrifying, nightmarish, traumatic, appalling, impendent, minacious, dangerous, unsettling, upsetting, menacing, bloodcurdling, unsafe, threatening
4 Syllables
infestive, unspeakable, dangersome, awesome, worrisome, spine-chilling, troublesome, minatory
5 Syllables
undescribable, comminatory, unutterable, inexpressible, indefinable
6 Syllables
intimidatory, incommunicable