THREATENING

baleful, forbidding, menacing, minacious, minatory, ominous, sinister, threatening

(adjective) threatening or foreshadowing evil or tragic developments; “a baleful look”; “forbidding thunderclouds”; “his tone became menacing”; “ominous rumblings of discontent”; “sinister storm clouds”; “a sinister smile”; “his threatening behavior”; “ugly black clouds”; “the situation became ugly”

heavy, lowering, sullen, threatening

(adjective) darkened by clouds; “a heavy sky”

Source: WordNet® 3.1

Etymology

Verb

threatening

present participle of threaten

Adjective

threatening (comparative more threatening, superlative most threatening)

Presenting a threat; menacing; frightening.

Noun

threatening (countable and uncountable, plural threatenings)

An act of threatening; a threat.

The butcher's boy — a fierce and beefy youth, who openly defied the dog, and waved him off with hurlings of his basket and threatenings of his feet, accompanied by growls of "Git out, yer beast!" — now entered silently […]

Source: Wiktionary

Threat"en*ing,

Definition: a. & n. from Threaten, v.

– Threat"en*ing*ly, adv. Threatening letters (Law), letters containing threats, especially those designed to extort money, or to obtain other property, by menaces; blackmailing letters.

THREATEN

Threat"en, v. t. [imp. & p. p. Threatened; p. pr. & vb. n. Threatening.] Etym: [OE. . See Threat, v. t.]

1. To utter threats against; to menace; to inspire with apprehension; to alarm, or attempt to alarm, as with the promise of something evil or disagreeable; to warn. Let us straitly threaten them, that they speak henceforth to no man in this name. Acts iv. 17.

2. To exhibit the appearance of (something evil or unpleasant) as approaching; to indicate as impending; to announce the conditional infliction of; as, to threaten war; to threaten death. Milton. The skies look grimly And threaten present blusters. Shak.

Syn.

– To menace.

– Threaten, Menace. Threaten is Anglo-Saxon, and menace is Latin. As often happens, the former is the more familiar term; the latter is more employed in formal style. We are threatened with a drought; the country is menaced with war. By turns put on the suppliant and the lord: Threatened this moment, and the next implored. Prior. Of the sharp ax Regardless, that o'er his devoted head Hangs menacing. Somerville.

Threat"en, v. i.

Definition: To use threats, or menaces; also, to have a threatening appearance. Though the seas threaten, they are merciful. Shak.

Source: Webster’s Unabridged Dictionary 1913 Edition