"one who or that which hooks" in any sense, agent noun from hook (v.). Meaning "prostitute" (by 1845) often is traced to the disreputable morals of the Army of the Potomac (American Civil War) under the tenure of Gen. "Fighting Joe" Hooker (early 1863), and the word might have been popularized by this association at that time (though evidence is wanting). But it is reported to have been in use in North Carolina c. 1845 ("[I]f he comes by way of Norfolk he will find any number of pretty Hookers in the Brick row not far from French's hotel. Take my advice and touch nothing in the shape of a prostitute when you come through Raleigh, for in honest truth the clap is there of luxuriant growth." letter quoted in Norman E. Eliason, "Tarheel Talk," 1956).
One early theory traces it to Corlear's Hook, a section of New York City.
HOOKER. A resident of the Hook, i.e. a strumpet, a sailor's trull. So called from the number of houses of ill-fame frequented by sailors at the Hook (i.e. Corlear's Hook) in the city of New York. [John Russell Bartlett, "Dictionary of Americanisms," 1859]
Or perhaps related to hooker "thief, pickpocket" (1560s).
But the word is likely a reference to prostitutes hooking or snaring clients. Hook in the figurative sense of "that by which anyone is attracted or caught" is recorded from early 15c.; and hook (v.) in the figurative sense of "catch hold of and draw in" is attested from 1570s; in reference to "fishing" for a husband or a wife, it was in common use from c. 1800. All of which makes the modern sense seem a natural step. Compare French accrocheuse, raccrocheuse, common slang term for "street-walker, prostitute," literally "hooker" of men.
The family name Hooker (attested from c. 975) would mean "maker of hooks," or else refer to an agricultural laborer who used a hook (compare Old English weodhoc "weed-hook").
c. 1200, "opposite of right," probably from Kentish and northern English forms of Old English *lyft "weak; foolish" (in lyft-adl "lameness, paralysis"). Compare East Frisian luf, Dutch dialectal loof "weak, worthless").
Sense of "opposite of right" is from the left being usually the weaker hand), a derived sense also found in cognate Middle Dutch and Low German luchter, luft. Compare Lithuanian kairys "left" and Lettish kreilis "left hand" both from a root that yields words for "twisted, crooked."
The usual Old English winstre/winestra "left" (adj.); "left hand," literally "friendlier," a euphemism used superstitiously to avoid invoking the unlucky forces connected with the left side (compare sinister). The Kentish word itself might have been originally a taboo replacement, if instead it represents PIE *laiwo- "considered conspicuous" (represented in Greek laios, Latin laevus, and Russian levyi). Greek also uses a euphemism for "left," aristeros "the better one" (compare also Avestan vairyastara- "to the left," from vairya- "desirable").
Meaning "being on the left-hand side" is from c. 1300. As an adverb from early 14c. For political senses, see left (n.). Used at least since c. 1600 in various senses of "irregular, illicit;" earlier proverbial sense was "opposite of what is expressed" (mid-15c.), for example over the left (shoulder) "not at all," added to a statement to negate or neglect what was just said (1705). To have two left feet "be clumsy" is attested by 1902.
Phrase out in left field "out of touch with pertinent realities" is attested from 1944, from the baseball fielding position that tends to be far removed from the play (left field in baseball attested by 1867; the fielding positions are from the point of view of the batter). The Parisian Left Bank (of the River Seine) has been associated with intellectual and artistic culture at least since 1893; Left Coast "Pacific Coast of the U.S." is by 1980s.
German link, Dutch linker "left" are said to be not directly related to these, being instead from Old High German slinc and Middle Dutch slink "left," related to Swedish linka "limp," slinka "dangle," and Old English slincan "crawl" (Modern English slink).