Etymology
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frumpy (adj.)
1746, "cross-tempered," probably from the frumps (n.) "bad temper" (1660s) and an earlier verb meaning "to mock, browbeat" (1550s), of obscure origin, perhaps imitative of a sneer or derisive snort. See also frump. Sense of "sour-looking, unfashionable" is from 1825, but this may be a shortening of frumple "to wrinkle, crumple" (late 14c.), from Middle Dutch verrompelen "to wrinkle," from ver- "completely" + rompelen "to rumple." Related: Frumpily; frumpiness.
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frump (n.)
"cross, unstylish person," especially a woman or girl, 1817, from a group of related words of uncertain origin: Frump (n.) "a mocking speech" (1550s), "a sneer or snort" (1580s); frump (v.) "to mock, flout, taunt" (1570s); frumps (n.) "ill-humor" (1660s); frumpish (adj.) "cross-tempered" (1640s); and compare frumpy.
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