Origin and history of left-wing

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").

The 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").

The meaning "being on the left-hand side" is from c. 1300. As an adverb from early 14c. For political senses, see left (n.).

It has been used at least since c. 1600 in various senses of "irregular, illicit;" the 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).

late 12c., wenge, "forelimb fitted for flight of a bird or bat," also the part of some insects resembling a wing in form or function, from Old Norse vængr "wing of a bird, aisle, etc." (cognate with Danish and Swedish vinge "wing"), a word of unknown origin, perhaps from a Proto-Germanic *we-ingjaz, suffixed form of PIE root *we- "blow" (source of Old English wawan "to blow."

Replaced Old English feðra (plural) "wings" (see feather (n.)). As "power of flight" from late 14c. (to take wing "take flight" is by 1704). By mid-14c. figuratively, "that by which (someone, something) ascends spiritually." To spread (one's) wings "develop one's powers" is by 1864.

The meaning "either of two divisions of an army" is recorded c. 1400, later extended to factions, political parties. As "part of a building projecting from one side of the main part" is by 1520s. The sense in reference to each of the side-scenes of the stage of a theater is by 1790.

The slang sense of earn (one's) wings is 1940s, from the wing-shaped badges awarded to air cadets on graduation. Phrase on a wing and a prayer is title of a patriotic song from late 1942 ("I'm Coming In On a Wing and a Prayer," lyrics Harold Adamson) about landing a damaged bomber.

What a show, what a fight

Boys, we really hit our target for tonight

How we sing as we limp through the air

Look below, there's our field over there

With our one motor gone

We can still carry on

Comin' in on a wing and a prayer

To be under (someone's) wing "protected by (someone)" is recorded from early 13c., the image is of a young bird and its mother.