very stupid—popularised by Jethro Tull’s ‘Thick as a Brick’ (1972), but already existed—in early use (19th century) applied to nouns such as ‘skull’ and ‘head’, used metonymically for ‘intelligence’
UK, 1879—when matters become difficult or serious—of obscure origin—perhaps originally in reference to a music-hall song of that title, interpreted from 1870 onwards by Annie Adams
a coin-operated phonograph (typically in a gaudy, illuminated cabinet) having a variety of records that can be selected by push button—USA, 1939—earlier appellation: jook organ (Florida, 1937)
to walk with arms extended, elbows and wrists bent at right angles, one arm up, one down—1962 in To Kill a Mockingbird—refers to the representation of the human body by the ancient Egyptians
a synthesizer designed to be held in the manner of a guitar, with one hand playing a keyboard while the other operates controls on an extended handle—USA, 1979—from ‘key-’ in ‘keyboard’ and ‘-tar’ in ‘guitar’
to do everything possible to achieve a result or effect—UK, 1865 (as ‘to pull out a few more stops’)—alludes to pulling out all the stops of an organ in order to produce a full and thrilling sound
from the image of a speeding explosive projectile—primary meaning (of a motorcar, an aircraft, a motorcycle, an animal, a person): to move very fast—later (also ‘to go down like a bomb’ and ‘to go down a bomb’): to be very successful or popular
a lively but ineffectual young upper-class man—UK, 1959—apparently coined in the 1950s by the British jazz manager James Godbolt after ‘Hoorah Henry’, coined in 1936 by the U.S. author Alfred Damon Runyon