Etymology
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unwanted (adj.)
1690s, from un- (1) "not" + past participle of want (v.).
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herbicide (n.)
"chemical that kills plants," used to destroy unwanted weeds, etc., 1888, originally a trademark name, from herb + -cide "killer."
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riddance (n.)

1530s, "a cleaning out, removal, clearance," from rid + -ance. The meaning "a deliverance from something superfluous or unwanted" is from 1590s. Good riddance, "a welcome relief from unpleasant company or an embarrassing connection" attested from 1650s. Shakespeare has gentle riddance (1590s); Middleton has fair riddance (1610s).

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remediate (v.)

"remedy, redress, repair or remove something unwanted, restore to a natural or proper state," by 1961, a back-formation from remediation. Shakespeare seems to use it as an adjective in "Lear" (1605). The older verb is simply remedy. Related: Remediated; remediating.

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Edsel 
notoriously unsuccessful make of car, introduced 1956 and named for Henry and Clara Ford's only child; figurative sense of "something useless and unwanted" is almost as old. Edsel is a family name, attested since 14c. (William de Egeshawe), from High Edser in Ewhurst, Surrey.
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kudzu (n.)
perennial climbing plant native to Japan and China, 1893, from Japanese kuzu. It was introduced in U.S. southeast as forage (1920s) and to stop soil erosion (1930s) but soon ran wild and became emblematic of anything unwanted that grows faster than it can be controlled.
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impend (v.)
"be about to happen" (usually of something unwanted), 1590s, from Latin impendere "to hang over;" figuratively "to be imminent, be near," from assimilated form of in- "into, in, on, upon" (from PIE root *en "in") + pendere "to hang" (from PIE root *(s)pen- "to draw, stretch, spin"). Literal sense in English is by 1780. Related: Impended; impending.
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abuse (n.)
Origin and meaning of abuse
mid-15c., "improper practice," from Old French abus (14c.), from Latin abusus "a using up" (see abuse (v.)). From 1570s as "violation, defilement" (surviving in self-abuse "masturbation," if at all). In reference to drugs by 1961. Modern use in reference to unwanted sexual activity is from late 20c. Earlier in Middle English was abusion "wicked act or practice, shameful thing, violation of decency" (early 14c.), "an insult" (mid-14c.), from Old French abusion, from Latin abusio.
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abuse (v.)
Origin and meaning of abuse
early 15c., "to misuse, misapply" (power, money, etc.), from Old French abuser "deceive, abuse, misuse" (14c.), from Vulgar Latin *abusare, from Latin abusus "an abusing; a using up," past participle of abuti "use up, consume," also "misuse, abuse, misapply, outrage," from ab "off, away from" (see ab-) + uti "use" (see use).

Also in reference to forbidden sexual situations from early 15c., but originally meaning incest, masturbation (self-abuse), homosexuality, prostitution, etc. From 1550s specifically as "to misuse sexually, ravish," but OED 2nd ed. marks this obsolete and the modern use "subject (someone) to unwanted sexual activity" is likely a fresh coinage from late 20c. Specifically of drugs, from 1968. Meaning "attack with harsh language, revile" is from c. 1600. Related: Abused; abusing.
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cold shoulder (n.)

1816, in the figurative sense of "icy reception, studied neglect or indifference," first in Sir Walter Scott, probably originally a literal figure (see cold (adj.)), but commonly used with a punning reference to "cold shoulder of mutton," considered a poor man's dish and thus, perhaps, something one would set out for an unwanted guest with deliberate intention to convey displeasure.

How often have we admired the poor knight, who, to avoid the snares of bribery and dependence, was found making a second dinner from a cold shoulder of mutton, above the most affluent courtier, who had sold himself to others for a splendid pension! ["No Fiction," 1820]

Originally with to show, later to give. As a verb from 1845; related: cold-shouldered. Also compare cold roast, old slang for "something insignificant." Cold pig was a 19c. term for throwing cold water on a sleeping person to wake him or her.

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