The Difference Between Ominous, Portentous, and Fateful

Ominous didn't always mean "foreshadowing evil." If you look closely, you can see the omen in ominous, which gave it the original meaning of "presaging events to come"—whether good or bad. It is ultimately derived from the Latin word omen, which is both an ancestor and a synonym of our omen. Today, however, ominous tends to suggest a menacing or threatening aspect. Its synonyms portentous and fateful are used similarly, but ominous is the most menacing of the three. It implies an alarming character that foreshadows evil or disaster. Portentous suggests being frighteningly big or impressive, but seldom gives a definite forewarning of calamity. Fateful implies that something is of momentous or decisive importance.