hack (v.1)youdaoicibaDictYouDict[hack 词源字典]
"to cut roughly, cut with chopping blows," c. 1200, from verb found in stem of Old English tohaccian "hack to pieces," from West Germanic *hakkon (cognates: Old Frisian hackia "to chop or hack," Dutch hakken, Old High German hacchon, German hacken), from PIE *keg- "hook, tooth" (see hook (n.)). Perhaps influenced by Old Norse höggva "to hew, cut, strike, smite" (which is unrelated, from PIE *kau- "to hew, strike;" see hew). Slang sense of "cope with" (as in can't hack it) is first recorded in American English 1955, with a sense of "get through by some effort," as a jungle (phrase hack after "keep working away at" is attested from late 14c.). To hack around "waste time" is U.S. slang, by 1955, perhaps originally of golfers or cabbies. Related: Hacked; hacking.[hack etymology, hack origin, 英语词源]
hack (v.2)youdaoicibaDictYouDict
"illegally enter a computer system," by 1984; apparently a back-formation from hacker. Related: Hacked; hacking (1975 in this sense). Earlier verb senses were "to make commonplace" (1745), "make common by everyday use" (1590s), "use (a horse) for ordinary riding" (1560s), all from hack (n.2).
phreak (n.)youdaoicibaDictYouDict
1972, originally in phone phreak, one of a set of technically creative people who electronically hacked or defrauded telephone companies of the day.
The phreaks first appeared on the US scene in the early 1960s, when a group of MIT students were found to have conducted a late night dialling experiment on the Defense Department's secret network. They were rewarded with jobs when they explained their system to Bell investigators. ... The name "phone phreak" identified the enthisiasts with the common underground usage of freak as someone who was cool and used drugs. ["New Scientist," Dec. 13, 1973]
The ph- in phone may have suggested the alteration, and this seems to be the original of the 1990s slang fad for substituting ph- for f- (as in phat).
wacky (adj.)youdaoicibaDictYouDict
"crazy, eccentric," 1935, variant of whacky (n.) "fool," late 1800s British slang, probably ultimately from whack "a blow, stroke," from the notion of being whacked on the head one too many times.
whack (v.)youdaoicibaDictYouDict
"to strike sharply," 1719, probably of imitative origin. The noun is from 1737. The word in out of whack (1885) is perhaps the slang meaning "share, just portion" (1785), which may be from the notion of the blow that divides, or the rap of the auctioneer's hammer. To have (or take) a whack at something "make an attempt" is from 1891. Related: Whacked; whacking. Whacked out is from 1969.
y-youdaoicibaDictYouDict
perfective prefix, in yclept, etc.; a deliberate archaism, introduced by Spenser and his imitators, representing an authentic Middle English prefix, from Old English ge-, originally meaning "with, together" but later a completive or perfective element, from Proto-Germanic *ga- "together, with" (also a collective and intensive prefix), from PIE *kom "beside, near, by, with" (cognate with Sanskrit ja-, Latin com-, cum-; see com-). It is still living in German and Dutch ge-, and survives, disguised, in some English words (such as alike, aware, handiwork).

Among hundreds of Middle English words it formed are yfallen, yhacked ("completely hacked," probably now again useful), yknow, ymarried, ywrought.