acumen

Noun

acumen (usually uncountable, plural acumens or acumina)

1. (usually) Quickness of perception or discernment; penetration of mind; the faculty of nice discrimination; acuity of mind.
   • "I am going to ask you a question that does not require much legal acumen to answer," said Lord Meersbrook to his attorney, when he called the next day in Lincoln's Inn;...1842, [anonymous collaborator of Letitia Elizabeth Landon], chapter XXXVII, in Lady Anne Granard; or, Keeping up Appearances. […], volume II, London: Henry Colburn, […], →OCLC, page 168
   • Sunning himself on the board steps, I saw for the first time Mr. Farquhar Fenelon Cooke.[…]A silver snaffle on a heavy leather watch guard which connected the pockets of his corduroy waistcoat, together with a huge gold stirrup in his Ascot tie, sufficiently proclaimed his tastes.[…]But withal...1897 December (indicated as 1898), Winston Churchill, chapter II, in The Celebrity: An Episode, New York, N.Y.: The Macmillan Company; London: Macmillan & Co., Ltd., →OCLC

   Synonyms:

   sharpness, penetration, keenness, shrewdness, acuteness, acuity, wits, foxiness, intelligence, canniness

2. (usually) A sharp, tapering point extending from a plant.
   • The black star of the corolla, characteristic of the original form, the manyfloweredness of the inflorescence (often connected with [3]—4 whirls), upper leaves in the inflorescence, adpression of the acumina of the calyx, its size, the closely situated anthers, long pistils, the length of the...1930, Prilozhenie, page 519
   • 11. S. boyacense. Resembles S. Rybinii from which it is distinguished by the greater dissection of the leaves, the longer calyx acumens, smaller anthers and coloured corolla.1956, S.M. Bukasov, Translation of THEORETICAL BASES OF PLAN BREEDING, page 6
3. (usually) A bony, often sharp, protuberance, especially that of the ischium.
   • The rostrum is the anterior extension of the carapace between the eyes. It ends in a more or less acute tip, or acumen, and may have a lateral spine on each side or bear a longitudinal keel (carina) on the dorsal surface.c. 1918, University of California, Pamphlets on Biology: Kofoid collection, Volume 1586, page 692
   • DIAGNOSIS—Rostrum usually with marginal spines, tubercles, or angles at base of acumen, and rarely with low medina carina.1981, Horton Holcombe Hobbs, The Crayfishes of Georgia: Issue 318 of Smithsonian contributions to zoology, Smithsonian Institution, page 486