Etymology
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beef up (v.)
"add strength," 1941, from college slang, from beef (n.) in slang sense of "muscle-power" (1851).
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boob tube (n.)
"television set," U.S. slang, by 1965, from boob "stupid person" + slang tube (n.) "television, television programming;" the original sets had vacuum tubes in them.
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stink eye (n.)
"dirty look," by 1972, perhaps from Hawaiian slang.
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boot camp (n.)
"training station for recruits," by 1941, U.S. Marines slang, said to be from boot (n.1) as slang for "recruit," which is attested by 1915 and supposedly dates from the Spanish-American War and is a synecdoche from boots "leggings worn by U.S. sailors."
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bush league (adj.)
"mean, petty, unprofessional," 1906, from baseball slang for the small-town baseball clubs below the minor league where talent was developed (by 1903), from bush (n.) in the adjectival slang sense of "rural, provincial," which originally was simple description, not a value judgment.
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zoot suit (n.)
1942, American English slang, the first element probably a nonsense reduplication of suit (compare reet pleat, drape shape from the same jargon).
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jerk off (v.)

slang, "perform male masturbation," by 1896, from jerk (v.) denoting rapid pulling motion + off (adv.). Compare come off "experience orgasm" (17c.). Farmer and Henley ("Slang and Its Analogues") also lists as synonyms jerk (one's) jelly and jerk (one's) juice. The noun jerk off or jerkoff as an emphatic form of jerk (n.2) is attested by 1968. As an adjective from 1957.

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cop out 

by 1942, noun ("a cowardly escape, an evasion") and verb ("sneak off, escape, give up without trying"), American English slang, perhaps from cop a plea (c. 1925) "plead guilty to lesser charges," which is probably from northern British slang cop "to catch" (a scolding, etc.); as in cop a feel "grope someone" (1930s); see cop (v.). Sense of "evade an issue or problem" is from 1960s.

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blind date (n.)
by 1921, U.S. college student slang, from blind (adj.) + date (n.3). Earliest attested use is in reference to the person; of the event by 1925.
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black box (n.)
1947, RAF slang for "navigational instruments;" later extended to any sort of apparatus that operates in a sealed container. Especially of flight recorders from c. 1964.
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