Synonyms of the word

threatening

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

alarming

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

baleful

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

cloudy

• adj. Covered with or characterised by clouds; overcast.
• adj. Not transparent or clear.
• adj. Uncertain; unclear.

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.

heavy

• adj. (of a physical object) Having great weight.
• adj. (of a topic) Serious, somber.
• adj. Not easy to bear; burdensome; oppressive.
• adj. (Britain, slang, dated) Good.
• adj. (dated, late 1960s, 1970s, US) Profound.
• adj. (of a rate of flow) High, great.
• adj. (slang) Armed.
• adj. (music) Louder, more distorted.
• adj. (of weather) Hot and humid.
• adj. (of a person) Doing the specified activity more intensely than most other people.
• adj. (of food) High in fat or protein; difficult to digest.
• adj. Of great force, power, or intensity; deep or intense.
• adj. Laden to a great extent.
• adj. Laden with that which is weighty; encumbered; burdened; bowed down, either with an actual burden, or with…
• adj. Slow; sluggish; inactive; or lifeless, dull, inanimate, stupid.
• adj. Impeding motion; cloggy; clayey.
• adj. Not raised or leavened.
• adj. Having much body or strength; said of wines or spirits.
• adj. (obsolete) With child; pregnant.
• adv. heavily.
• adv. (India, colloquial) very.
• n. A villain or bad guy; the one responsible for evil or aggressive acts.
• n. (slang) A doorman, bouncer or bodyguard.
• n. (aviation) A large multi-engined aircraft.
• v. (often with "up") To make heavier.
• v. To sadden.
• v. (Australia, New Zealand, informal) To use power and/or wealth to exert influence on, e.g., governments…
• adj. Having the heaves.

lowering

• v. present participle of lower.
• adj. That lowers or frowns.
• n. The act of something being lowered.

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.

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.

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.

sullen

• adj. Having a brooding ill temper; sulky.
• adj. Gloomy; dismal; foreboding.
• adj. Sluggish; slow.
• adj. (obsolete) Lonely; solitary; desolate.
• adj. (obsolete) Mischievous; malignant; unpropitious.
• adj. (obsolete) Obstinate; intractable.
• n. (obsolete) One who is solitary, or lives alone; a hermit.
• n. Sullen feelings or manners; sulks; moroseness.