minacious (adj.)

c. 1300, "declaration of hostile intent," also (early 14c.) "a threat or act of threatening," from Old French menace "menace, threat" (9c.), from Vulgar Latin minacia "threat, menace" (also source of Spanish amenaza, Italian minaccia), singular of Latin minaciæ "threatening things," from minax (genitive minacis) "threatening," from minari "threaten; jut, project," from minæ "threats; projecting points," from PIE root *men- (2) "to project." Applied to persons from 1936.

word-forming element making adjectives from nouns, meaning "having, full of, having to do with, doing, inclined to," from Old French -ous, -eux, from Latin -osus (compare -ose (1)). In chemistry, "having a lower valence than forms expressed in -ic."

Proto-Indo-European root meaning "to project." 

It forms all or part of: amenable; amount; cismontane; demeanor; dismount; eminence; eminent; imminence; imminent; menace; minacious; minatory; mons; montage; montagnard; monte; mount (n.1) "hill, mountain;" mount (v.) "to get up on;" mountain; mountebank; mouth; Osmond; Piedmont; promenade; prominence; prominent; promontory; remount; surmount; ultramontane.

It is the hypothetical source of/evidence for its existence is provided by: Sanskrit manya "nape of the neck;" Latin mons "mountain," eminere "to stand out;" Old Irish muin "neck," Welsh mwnwgl "neck," mwng "mane;" Welsh mynydd "mountain."