See fateful in Webster's New World Roget's A-Z Thesaurus II
adjective
So critically decisive as to affect the future:
fatal, momentous. See decideGoverned and decided by or as if by fate:
fated. See certainCausing ruin or destruction:
calamitous, cataclysmal, cataclysmic, catastrophic, destructive, disastrous, fatal, ruinous. See helpPortending future disaster:
apocalyptic, apocalyptical, baneful, dire, direful, fire-and-brimstone, grave2, hellfire, ominous, portentous, unlucky. See luck, warn
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