Etymology
Advertisement
lucky (adj.)

mid-15c., of persons; 1540s, of actions or objects, "likely to bring luck;" from luck (n.) + -y (2). Meaning "occurring by chance" is 1590s. Related: Luckier; luckiest; luckiness.

Lucky break is attested from 1884 in billiards; 1872 as "failure or break-down which turns out to be fortunate." Lucky accident is from 1660s. Lucky dog "unusually lucky person" is from 1842. Lucky Strike as the name of a U.S. brand of cigarettes (originally chewing tobacco) popular in the World War II years is said to date from 1871. Its popularity grew from 1935 when the brand's maker picked up sponsorship of radio's "Your Hit Parade."

Related entries & more 
Advertisement
luckily (adv.)

"fortunately, in a lucky manner; by good fortune, with a favorable outcome," 1520s, from lucky + -ly (2).

Related entries & more 
unlucky (adj.)
1520s, "marked by misfortune or failure," from un- (1) "not" + lucky (adj.). Similar formation in West Frisian unlokkich, Mliddle Low German unluckich. Sense of "boding ill" is recorded from 1540s; that of "having bad luck" is from 1550s; that of "bringing bad luck" is from 1580s. Related: Unluckily; unluckiness.
Related entries & more 
happy-go-lucky (adv.)
also happy go lucky, 1670s, "haphazard, in any way one pleases; every man for himself." Earlier as happy-be-lucky (1630s). The adjective, of persons, recorded from 1835, "careless," hence "carefree."
Related entries & more 
chancy (adj.)

1510s, "lucky, foreboding good fortune," from chance (n.) + -y (2). Meaning "uncertain, subject to risk" is recorded from 1860.

Related entries & more 
Advertisement
fluke (n.2)
"lucky stroke, chance hit," 1857, also flook, said to be originally a lucky shot at billiards, of uncertain origin. Century Dictionary connects it with fluke (n.1) in reference to the whale's use of flukes to get along rapidly (to go a-fluking or some variant of it, "go very fast," is in Dana, Smyth, and other sailors' books of the era). OED (2nd ed. print) allows only that it is "Possibly of Eng. dialectal origin."
Related entries & more 
fortunate (adj.)
late 14c., "having good fortune; bringing good fortune," from Latin fortunatus "prospered, prosperous; lucky, happy," past participle of fortunare "to make prosperous," from fortuna (see fortune). Fortunate Islands "mythical abode of the blessed dead, in the Western Ocean" (early 15c.; late 14c. as Ilondes of fortune) translates Latin Fortunatae Insulae.
Related entries & more 
uncanny (adj.)

1590s, in a now-obsolete meaning "mischievous, malicious;" also in 17c., "careless, incautious; unreliable, not to be trusted," from un- (1) "not" + canny (q.v.) in its old Scots and Northern English sense of "skillful, prudent, lucky" (it is a doublet of cunning).

Canny had also a sense of "superstitiously lucky; skilled in magic." In Wright's "English Dialect Dictionary" (1900) the first sense of uncanny as used in Scotland and the North is "awkward, unskilful; careless; imprudent; inconvenient." The second is "Unearthly, ghostly, dangerous from supernatural causes ; ominous, unlucky ; of a person : possessed of supernatural powers".

From 1773, uncanny appears in popular literature from the North (Robert Fergusson, Scott), with reference to persons and in a sense of "not quite safe to trust or deal with through association with the supernatural." By 1843 it had a general sense in English of "having a supernatural character, weird, mysterious, strange." (OED notes this as "Common from c 1850"; Borges considers it untranslatable but notes that German unheimlich answers to it.)

The Scottish writers also use it with the meanings "unpleasantly hard; dangerous, unsafe."

Related entries & more 
infortunate (adj.)
"unlucky, luckless," late 14c., from Latin infortunatus, from in- "not, opposite of" (see in- (1)) + fortunatus "prospered, prosperous; lucky, happy" (see fortunate (adj.)). Also used in medieval astrology in reference to the supposed malevolent influence of certain positions or combinations of planets. The word lies beneath the "obsolete" headstone in OED. Related: infortune (n.); infortunacy.
Related entries & more 
felicitate (v.)
1620s, "to render happy" (obsolete); 1630s, "to reckon happy;" from Late Latin felicitatus, past participle of felicitare "to make happy," from Latin felicitas "fruitfulness, happiness," from felix "fruitful, fertile; lucky, happy" (see felicity). Meaning "congratulate, compliment upon a happy event" is from 1630s. Related: Felicitated; felicitating. Little-used alternative verb form felicify (1680s) yielded adjective felicific (1865).
Related entries & more