late 14c., "injurious, dangerous," also "absurd, illogical" (senses now obsolete), from Latin inconvenientem (nominative inconveniens) "unsuitable, not accordant, dissimilar," from in- "not, opposite of" (see in- (1)) + convenientem (see convenient). In early 15c., "inappropriate, unbecoming, unnatural;" also, of an accused person, "unlikely as a culprit, innocent." Sense of "troublesome, incommodious, awkward" is recorded from 1650s.

"spice made from dry outer husk of nutmeg," late 14c., from Old French macis (in English taken as a plural and stripped of its -s), a word of uncertain origin, sometimes said to be a scribal error for Latin macir, the name of a red spicy bark from India, but OED finds this etymology unlikely.

a preparation of Cannabis sativa for use as an intoxicant, generally by smoking, 1918, altered by influence of Spanish proper name Maria Juana "Mary Jane" from mariguan (1894), from Mexican Spanish marihuana, which is of uncertain origin. As the plant was not native to Mexico, a native source for the word seems unlikely.

Greek Tantalos, ancient mythical king of Phrygia, a name of uncertain origin, perhaps literally "the Bearer" or "the Sufferer," by dissimilation from *tal-talos, a reduplication of PIE root *tele- "to bear, carry, support" (see extol), in reference to his long endurance, but Watkins finds this "unlikely" and Beekes writes that "An IE interpretation is most improbable." Compare tantalize.

also long-shot, in the figurative sense of "something unlikely," 1867, from long (adj.) + shot (n.). The notion is of a shot at a target from a great distance, thus difficult to make. The phrase by a long shot "by a considerable amount," frequently negative, is attested by 1830, American English colloquial. The cinematic sense of the noun phrase is from 1922. As an adjective by 1975.