mysterious (adj.)

1610s, "full of mystery, obscure, not revealed or explained," from Latin mysterium (see mystery (n.1)) + -ous. Related: Mysteriously; mysteriousness. Earlier in same sense was mysterial (early 15c.), from Late Latin mysterialis.

Mysterious is the most common word for that which is unknown and excites curiosity and perhaps awe; the word is sometimes used where mystic would be more precise. Mystic is especially used of that which has been designed to excite and baffle curiosity, involving meanings in signs, rites, etc., but not with sufficient plainness to be understood by any but the initiated. [Century Dictionary]
God moves in a mysterious way,
His wonders to perform;
He plants his footsteps in the sea,
And rides upon the storm
[Cowper, from the "Olney Hymns," 1779]

Related: Mysteriously; mysteriousness.

Related entries & more 
cryptic (adj.)

1630s, "hidden, occult, mystical," from Late Latin crypticus, from Greek kryptikos "fit for concealing," from kryptos "hidden" (see crypt). Meaning "mysterious, enigmatic" is attested by 1920. Related: Cryptically.

Related entries & more 
mystify (v.)

1798, "to make obscure, obscure the meaning of;" 1814, "perplex purposely," from French mystifier (1772), a verb formed irregularly from mystique "mysterious" (see mystic (adj.)) + -fier "to make" (see -fy). Related: Mystified; mystifying.

Related entries & more 
inscrutable (adj.)
"that cannot be discovered by searching, mysterious," c. 1500, from Late Latin inscrutabilis, from in- "not, opposite of" (see in- (1)) + *scrutabilis, from scrutari "examine, ransack" (see scrutiny). Related: Inscrutably; inscrutableness.
Related entries & more 
dido (n.)

"prank, caper," 1792, slang, perhaps from the name of the legendary Carthaginian queen in the "Aeneid." Usually in phrase to cut didoes. Century Dictionary repeats a story that attributes it to her having made a bargain for as much land as could be covered by a hide, then cutting the hide into a long, thin strip so as to enclose a large tract, but this is not in the early references to the term, which regard its origin as mysterious.

Related entries & more 
mystic (adj.)

late 14c., mistike, "spiritually allegorical, pertaining to mysteries of faith," from Old French mistique "mysterious, full of mystery" (14c.), or directly from Latin mysticus "mystical, mystic, of secret rites" (source also of Italian mistico, Spanish mistico), from Greek mystikos "secret, mystic, connected with the mysteries," from mystes "one who has been initiated" (see mystery (n.1)).

Meaning "pertaining to occult practices or ancient religions" is recorded by 1610s. That of "hidden from or obscure to human knowledge or comprehension" is by 1630s.

Related entries & more 

in cookery, denoting a method of grilling a game bird after splitting it open along the spine and laying it flat; a word of obscure origin.

It originated in Ireland in the late eighteenth century as a noun, referring to the bird thus dispatched, and indeed it may have been based on the verb dispatch, with the addition of cock. Another probable influence is the earlier spitchcock, a word of mysterious origin denoting similar treatment meted out to eels and other fish. [Ayto, "Diner's Dictionary"]
Related entries & more 
bobby sox (n.)

also bobby socks, 1943, from diminutive of bob (n.2) + sox. So called because they are "shortened" compared to knee-socks. Derivative bobby-soxer "adolescent girl," especially with reference to fans of popular crooners, first attested 1944.

Months ago colored bobby sox folded at the top were decreed, not by anyone or any group but, as usual, by a sudden mysterious and universal acceptance of the new idea. Now no teen-ager dares wear anything but pure white socks without a fold. [Life magazine, Dec. 11, 1944]
Related entries & more 
jinx (n.)

1911, American English, originally baseball slang; perhaps ultimately from jyng "a charm, a spell" (17c.), originally "wryneck" (also jynx), a bird used in witchcraft and divination, from Latin iynx "wryneck," from Greek iynx. Jynx was used in English as "a charm or spell" from 1690s.

Most mysterious of all in the psychics of baseball is the "jinx," that peculiar "hoodoo" which affects, at times, a man, at other times a whole team. Let a man begin to think that there is a "jinx" about, and he is done for for the time being. ["Technical World Magazine," 1911]

 The verb is 1912 in American English, from the noun. Related: Jinxed; jinxing. 

Related entries & more 
mesmerism (n.)

"the doctrine that one person can exercise influence over the will and nervous system of another and produce certain phenomena by virtue of a supposed emanation called animal magnetism," 1798, from French mesmérisme, named for Franz Anton Mesmer (1734-1815), Austrian physician who developed a theory of animal magnetism and a mysterious body fluid which allows one person to hypnotize another and propounded it in 1778 in Paris. The word, if still used is practically synonymous with hypnotism or artificial somnambulism. Another similar word for the same effect was braidism. An old term for "hypnotic suggestion" was mesmeric promise. Related: Mesmerist

Related entries & more