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