1540s, "drive away," from Latin exterminatus, past participle of exterminare "drive out, expel, put aside, drive beyond boundaries," also, in Late Latin "destroy," from phrase ex termine "beyond the boundary," from ex "out of" (see ex-) + termine, ablative of termen "boundary, limit, end" (see terminus).

Meaning "destroy utterly" is from 1640s in English, a sense found in equivalent words in French and in the Vulgate; earlier in this sense was extermine (mid-15c.). Related: Exterminated; exterminating.

c. 1400, "an angel who expels (people from a country)," from Late Latin exterminator, from past-participle stem of Latin exterminare  "drive out, expel, put aside, drive beyond boundaries," also, in Late Latin "destroy" (see exterminate). As a substance for ridding a place of rats, etc., by 1848; as a person whose job it is to do this, by 1938. Old English glossed Latin exterminator with ofdræfere ("off-driver").

early 15c., "eradicate, exterminate," also "conquer, capture by fighting," from Old French expugner, from Latin expugnare "to take by assault, storm, capture" (source also of Spanish expugnar, Italian espugnare), from ex (see ex-) + pugnare "to fight" (see pugnacious). Related: Expugned; expugnable.

c. 1300, minen, "to dig a tunnel under fortifications to overthrow them," from mine (n.1) or from Old French miner "to dig, mine; exterminate," from the French noun. From mid-14c. as "to dig in the earth" (in order to obtain minerals, treasure, etc.). Figurative meaning "ruin or destroy by slow or secret methods" is from mid-14c. Transitive sense of "to extract by mining" is from late 14c. For the sense of "to lay (explosive) mines," see mine (v.2). Related: Mined; mining.

"female pudenda," 1650s (earlier mawkine, 1530s), apparently a variant of malkin in its sense of "mop." Meaning "artificial vagina or 'counterfeit hair for a woman's privy parts' " [Grose] is attested from 1610s. According to "The Oxford Companion to the Body," the custom of wearing merkins dates from mid-15c., was associated with prostitutes, and was to disguise a want of pubic hair, either shaved off to exterminate body lice or a result of venereal disease.

This put a strange Whim in his Head; which was, to get the hairy circle of [a prostitute's] Merkin .... This he dry'd well, and comb'd out, and then return'd to the Cardinall, telling him, he had brought St. Peter's Beard. [Alexander Smith, "A Complete History of the Lives and Robberies of the most notorious Highwaymen," 1714]

late 15c., "reciprocally given and received," originally of feelings, from Old French mutuel (14c.), from Latin mutuus "reciprocal, done in exchange," from PIE root *mei- (1) "to change, go, move," "with derivatives referring to the exchange of goods and services within a society as regulated by custom or law" [Watkins].

The meaning "common" is from 1630s. "Used in this sense loosely and improperly (but not infrequently, and by many writers of high rank), especially in the phrase a mutual friend" [Century Dictionary].

That is common which pertains equally to two or more persons or things. That is mutual which is freely interchanged: mutual love, affection, hatred. The word is sometimes incorrectly used for common: our mutual friend, a phrase of very frequent occurrence, no doubt owing to the perfectly correct 'mutual friendship.' [J.H.A. Günther, "English Synonyms Explained & Illustrated," Groningen, 1904]

Mutual Admiration Society (1851) seems to have been coined by Thoreau. Mutual fund is recorded from 1950.

The Cold War's mutual assured destruction is attested from 1966. Assured destruction was a 1962 term in U.S. military policy circles in reference to nuclear weapons as a deterrent, popularized c. 1964 by Robert McNamara, U.S. Secretary of Defense under Lyndon Johnson, e.g. statement before House Armed Services Committee, Feb. 18, 1965. The notion was "the minimum threat necessary to assure deterrence: the capability to exterminate not less than one third of the Union of Soviet Socialist Republics' (USSR) population in a retaliatory nuclear attack." [Martin Folly, "Historical Dictionary of U.S. Diplomacy During the Cold War"].

By 1964, as the Soviet Union caught up to NATO in ICBMs, the mutual was added, perhaps first by Donald Brennan, conservative defense analyst and a public critic of the policy, who also noted the acronym MAD.)