Online Etymology Dictionary

happy (adv.): late 14c., from happy (adj.).
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."
Hapsburg: European dynasty, from German Habsburg, from the name of a castle on the Aar in Switzerland, originally Habichtsburg, literally "Hawk's Castle."
haptic (adj.): "pertaining to the sense of touch," 1890, from Greek haptikos "able to come into contact with," from haptein "to fasten" (see apse).
haptics (n.): 1895, from haptic; see -ics.
hara-kiri (n.): "suicide by disembowelment," 1856, from Japanese, literally "belly-cutting," the colloquial word for what is formally called seppuku "cut open the stomach;" from hara "belly" + kiri "to cut." Sometimes erroneously written hari-kari.
haram (adj.): in Islamic terminology, "forbidden;" see harem.
harangue (n.): mid-15c., arang, Scottish (in English from c. 1600), from Middle French harangue "a public address" (14c.), from Old Italian aringo "public square, platform; pulpit; arena," from a Germanic source such as Old High German hring "circle" (see ring (n.1)) on the notion of "circular gathering," with an -a- inserted to ease Romanic pronunciation of Germanic hr- (compare hamper (n.1)). But Watkins and Barnhart suggest a Germanic compound, *harihring "circular gathering, assembly," literally "host-ring, army-ring," with first element *hari- "war-band, host" (see harry (v.)). From the same Germanic "ring" root via Romanic come rank (n.), range (v.), arrange.
harangue (v.): 1650s, from French haranguer (15c.), from Middle French harangue (see harangue (n.)). Related: Harangued; haranguing.
harass (v.): 1610s, "to lay waste, devastate" (obsolete); 1620s, "to vex by repeated attacks," from French harasser "tire out, vex" (16c.), which is of uncertain origin; possibly from Old French harer "stir up, provoke; set a dog on," and perhaps blended with Old French harier "to harry, draw, drag" [Barnhart]. Related: Harassed; harassing.
harassment (n.): 1753, from harass + -ment.
harbinger (n.): late 15c., herbengar "one sent ahead to arrange lodgings" (for a monarch, an army, etc.), alteration of Middle English herberger "provider of shelter, innkeeper" (late 12c.), from Old French herbergeor "one who offers lodging, innkeeper," agent noun from herbergier "provide lodging," from herber "lodging, shelter," from Frankish *heriberga "lodging, inn" (cognate with Old Saxon, Old High German heriberga "army shelter"), from Germanic compound *harja-bergaz "shelter, lodgings," which is also the source of harbor (n.). Sense of "forerunner, that which precedes and gives notice of the coming of another" is mid-16c. Intrusive -n- is 15c. (see messenger). As a verb, from 1640s (harbinge "to lodge" is late 15c.).
harbor (n.): "lodging for ships; sheltered recess in a coastline," early 12c., a specialized sense of Middle English herberwe "temporary dwelling place, quarters, lodgings; an inn; the camp of an army in the field," probably from Old English here-beorg (West Saxon), *here-berg (Anglian) "lodgings, quarters," from Proto-Germanic compound *harja-bergaz "shelter, lodgings," from *heri "army, host" (see harry (v.)) + *burzjan- "protection, shelter" (see bury (v.)). Perhaps modeled on Old Norse herbergi "room, lodgings, quarters."
harbor (v.): Old English herebeorgian "take up quarters, lodge, shelter oneself" (cognate with Old Norse herbergja, Old High German heribergon, Middle Dutch herbergen), verbal formation from here-beorg "lodgings, quarters" (see harbor (n.)). Meaning "give shelter to, protect" is from mid-14c. Figuratively, of thoughts, etc., from late 14c. Related: Harbored; harboring.
harbour: chiefly British English spelling of harbor (n. and v.); for spelling, see -or. In this case it is considered to be without etymological justification and probably by analogy of labour.
hard (adj.): Old English heard "solid and firm, not soft," also, "difficult to endure, carried on with great exertion," also, of persons, "severe, rigorous, harsh, cruel," from Proto-Germanic *hardu- (source also of Old Saxon hard, Old Frisian herd, Dutch hard, Old Norse harðr "hard," Old High German harto "extremely, very," German hart, Gothic hardus "hard"), from PIE *kortu- (source also of Greek kratos "strength," kratys "strong"), suffixed form of root *kar-/*ker- "hard."

Meaning "difficult to do" is from c. 1200. Of water, in reference to the presence of mineral salts, 1650s; of consonants, 1775. Hard of hearing preserves obsolete Middle English sense of "having difficulty in doing something." In the sense "strong, spiritous, fermented" from 1789 (as in hard cider, etc.), and this use probably is the origin of that in hard drugs (1955). Hard facts is from 1853; hard news in journalism is from 1918. Hard copy (as opposed to computer record) is from 1964; hard disk is from 1978; the computer hard drive is from 1983. Hard times "period of poverty" is from 1705. Hard money (1706) is specie, as opposed to paper. Hence 19c. U.S. hard (n.) "one who advocates the use of metallic money as the national currency" (1844). To play hard to get is from 1945. Hard rock as a pop music style recorded from 1967. To do something the hard way is from 1907.
hard (adv.): Old English hearde "firmly, severely," from hard (adj.). Meaning "with effort or energy, with difficulty" is late 14c.
hard hat (n.): also hardhat, hard-hat, late 14c., "helmet," from hard (adj.) + hat (n.). From 1935 as "derby hat;" meaning "safety helmet" is from 1953; used figuratively for "construction worker" from 1970.
hard-bitten (adj.): "tough, tough in a fight," literally "given to hard biting," 1715, originally of hunting dogs, from hard (adv.) + bitten, with the past participle used actively (as in free-spoken).
hard-boiled (adj.): also hardboiled, 1723 in reference to eggs, "cooked so long as to be solid," from hard (adj.) + boiled. In transferred sense "severe, tough," from 1886.
hard-cover (adj.): of books, 1949, from hard (adj.) + cover (n.).
hard-fought (adj.): 1660s, from hard (adv.) + fought.
hard-headed (adj.): also hardheaded, 1580s, "stubborn," from hardhead "dull person" (1510s), from hard (adj.) + head (n.). Meaning "practical, shrewd" is attested from 1779. Compare Dutch hardhoofdig "stupid."
hard-hearted (adj.): also hardhearted, "obdurate, unfeeling," c. 1200, heard-iheorted," from hard (adj.) + hearted. Sometimes in Middle English also meaning "bold, courageous" (c. 1400). Related: Hard-heartedly; hard-heartedness. In late Old English and early Middle English, hard-heort meant both "hard-hearted" (adj.) and "hard-hearted person" (n.).
hard-line (adj.): "uncompromising," 1958, originally in reference to Soviet communist policies, from the noun phrase (see hard (adj.) + line (n.)) in the political sense. Related: Hard-liner (1963).
hard-nosed (adj.): "stubborn," 1927, from hard (adj.) + nose (n.). Earlier of bullets or shells with hard tips, and of dogs that had difficulty following a scent. Not in common use before 1950s, when it begins to be applied to tough or relentless characters generally (Damon Runyon characters, U.S. Marines, Princeton professors, etc.). Soft-nosed seems to have been used only of bullets.
hard-on (n.): "penile erection," 1922, earlier as an adjective (1893), from hard + on.
hard-shell (adj.): 1838 of Baptists (figuratively); 1798 of clams; see hard (adj.) + shell (n.). Hard-shelled is from 1610s.
hard-up (adj.): "in difficulties," especially "short of money," 1821, slang; it was earlier a nautical expression, in reference to steering.
hard-wired (adj.): also hardwired, 1969, in computing, "with permanently connected circuits performing unchangeable functions;" transferred to human brains from 1971; from hard (adv.) + wire (v.).
hard-working (adj.): also hardworking, 1708, from hard (adv.) + working (adj.).
hardback (n.): "type of book bound in stiff boards," 1954, from hard (adj.) + back (n.).
hardball (n.): 1883 as the name of a game, from hard (adj.) + ball (n.1). The figurative sense of "tough, uncompromising behavior" is from 1973.
hardcore: also hard-core; 1936 (n.); 1951 (adj.); from hard (adj.) + core (n.). Original use seems to be among economists and sociologists, in reference to unemployables. Extension to pornography is attested by 1966. Also the name of a surfacing material.
harden (n.): c. 1200, transitive, "make (something) hard," from hard (adj.) + -en (1). Intransitive meaning "to become hard" is late 14c. The earlier verb was simply hard, from Old English heardian. Related: Hardened; hardening.
hardened (adj.): past participle adjective from harden (v.). Figurative sense of "unfeeling" is from late 14c.
hardener (n.): 1610s, from harden + -er (1).
hardly (adv.): c. 1200, "in a hard manner, with great exertion or effort," from Old English heardlice "sternly, severely, harshly; bravely; excessively" (see hard (adj.) + -ly (2)). Hence "assuredly, certainly" (early 14c.). Main modern sense of "barely, just" (1540s) reverses this, via the intermediate meaning "not easily, with trouble" (early 15c.). Formerly with superficial negative (not hardly). Similar formation in Old Saxon hardliko, German härtlich, Old Danish haardelig.
hardness (n.): Old English heardnes; see hard (adj.) + -ness. Meaning "difficulty of action or accomplishment" is late 14c.
hardscrabble (n.): in popular use from c. 1826 as a U.S. colloquial name for any barren or impoverished place "where a livelihood may be obtained only under great hardship and difficulty" [OED]; from hard (adj.) + noun from scrabble (v.). Noted in 1813 as a place-name in New York state; first recorded in journals of Lewis and Clark (1804) as the name of a prairie. Perhaps the original notion was "vigorous effort made under great stress," though this sense is recorded slightly later (1812). As an adjective by 1845.
hardship (n.): c. 1200, "quality of being hard" (obsolete), from hard (adj.) + -ship. Meaning "disadvantage, suffering, privation" is c. 1400.
hardtack (n.): "ship's biscuit," 1830, from hard (adj.) + tack (n.3); soft-tack was soft wheaten bread.
hardware (n.): mid-15c., "small metal goods," from hard (adj.) + ware (n.). In the sense of "physical components of a computer" it dates from 1947. Hardware store attested by 1789.
hardwood (n.): 1560s, from hard (adj.) + wood (n.). That from deciduous trees, as distinguished from that from pines and firs.
hardy (adj.): c. 1200, "bold, daring, fearless," also "presumptuous, audacious," from Old French hardi "bold, brave, courageous; confident, presumptuous," from past participle of hardir "to harden, be or make bold," from Frankish *hardjan "to make hard" (source also of Old Frisian herda, Old High German herten, Old Norse herða, Gothic gahardjan "make hard"), from Proto-Germanic *hardu- (see hard (adj.)). Sense influenced by English hard. Of plants, "able to survive in the open year-round," 1660s. Related: Hardily; hardiness. Hardhede "physical hardiness" is attested from early 15c.
hare (n.): Old English hara "hare," from West Germanic *hasan- (source also of Old Frisian hasa, Middle Dutch haese, Dutch haas, Old High German haso, German Hase), of uncertain origin; possibly the original sense was "gray" (compare Old English hasu, Old High German hasan "gray"), from PIE *kas- "gray" (source also of Latin canus "white, gray, gray-haired"). Perhaps cognate with Sanskrit sasah, Afghan soe, Welsh ceinach "hare." Rabbits burrow in the ground; hares do not.
þou hast a crokyd tunge heldyng wyth hownd and wyth hare. ["Jacob's Well," c. 1440]
hare (v.): "to harry, harass," 1520s; meaning "to frighten" is 1650s; of uncertain origin; connections have been suggested to harry (v.) and to hare (n.). Related: Hared; haring.
Hare Krishna (adj.): 1970, from the title of a Hindu chant or mantra, from Hindi hare "O God!" + Krishna, name of an incarnation of the god Vishnu.
hare-brained (adj.): also harebrained, 1540s, from hare-brain "giddy or reckless person" (1540s), probably from hare (n.), on notion of "flighty, skittish."
hare-lip (n.): also harelip, 1560s, from hare (n.) + lip (n.). So called for resemblance.