Synonyms of the word

ominous

• adj. Of or pertaining to an omen or to omens; being or exhibiting an omen; significant.
• adj. Specifically, giving indication of a coming ill; being an evil omen; threatening; portentous; inauspicious.

alarming

• v. present participle of alarm.
• adj. causing apprehension, fear or alarm; frightening.

baleful

• adj. Portending evil; ominous.
• adj. Miserable, wretched, distressed, suffering.

forbidding

• adj. highly unpleasant or disagreeable.
• adj. threatening or menacing.
• v. present participle of forbid.
• n. The act by which something is forbidden; a prohibition.

ill

• adj. (obsolete) Evil; wicked (of people).
• adj. (archaic) Morally reprehensible (of behaviour etc.); blameworthy.
• adj. Indicative of unkind or malevolent intentions; harsh, cruel.
• adj. Unpropitious, unkind, faulty, not up to reasonable standard.
• adj. Unwell in terms of health or physical condition; sick.
• adj. Having an urge to vomit.
• adj. (hip-hop slang) Sublime, with the connotation of being so in a singularly creative way.
• adj. (slang) Extremely bad (bad enough to make one ill). Generally used indirectly with to be.
• adv. Not well; imperfectly, badly; hardly.
• n. (often pluralized) Trouble; distress; misfortune; adversity.
• n. Harm or injury.
• n. Evil; moral wrongfulness.
• n. A physical ailment; an illness.
• n. (US, slang) PCP, phencyclidine.

inauspicious

• adj. Not auspicious; ill-omened; unfortunate; unlucky; unfavorable.

menacing

• adj. Suggesting imminent harm.
• adj. Threatening.
• v. present participle of menace.
• n. The act of making menaces or threats.

minacious

• adj. (now rare) Threatening, menacing.

minatory

• adj. Threatening, menacing.

sinister

• adj. Inauspicious, ominous, unlucky, illegitimate (as in bar sinister).
• adj. Evil or seemingly evil; indicating lurking danger or harm.
• adj. Of the left side.
• adj. (heraldry) On the left side of a shield from the wearer's standpoint, and the right side to the viewer.
• adj. (obsolete) Wrong, as springing from indirection or obliquity; perverse; dishonest.

threatening

• v. present participle of threaten.
• adj. Presenting a threat; menacing; frightening.
• n. An act of threatening; a threat.

unpropitious

• adj. not propitious; unfavourable, untimely.