▪ I. obtuse, a.
(əbˈtjuːs)
[ad. L. obtūs-us dulled, blunt, pa. pple. of obtundĕre to obtund. Cf. F. obtus, -use (1542 in Hatz.-Darm.).]
Blunt (in various senses): opp. to acute.
1. lit. Of a blunt form; not sharp or pointed: esp. in Nat. Hist. of parts or organs of animals or plants. The opposite of acute.
| 1589 Puttenham Eng. Poesie ii. xi[i]. (Arb.) 114 Such shape as might not be sharpe..to passe as an angle, nor so large or obtuse as might not essay some issue out with one part moe then other as the rounde. 1657 S. Purchas Pol. Flying-Ins. 6 Their tails are somewhat sharp (the Drones more obtuse). 1660 Boyle New Exp. Phys. Mech. xxxix. 322 An Oval Glass..with a short Neck at the obtuser end. 1753 Chambers Cycl. Supp. s.v. Leaf, Obtuse Leaf, one terminated by the segment of a circle. 1767 Gooch Treat. Wounds I. 237 A blow with an obtuse weapon. 1845 Lindley Sch. Bot. i. (1858) 10 Leaves are obtuse, or acute, in the ordinary sense of those words. 1877–84 Hulme Wild Fl. p. viii, Spur stout, and obtuse. |
2. Geom. Of a plane angle: Greater than a right angle; exceeding 90°.
obtuse bisectrix: the line bisecting an obtuse angle, e.g. between the optic axes of a crystal. obtuse cone: a cone of which the section by a plane through the axis has an obtuse angle at the vertex. obtuse hyperbola: a hyperbola lying within the obtuse angles between its asymptotes.
| 1570 Billingsley Euclid i. def. x. 3 An obtuse angle is that which is greater then a right angle. 1633 P. Fletcher Purple Isl. iii. xxi, Into two obtuser angles bended. 1701 Grew Cosm. Sacra ii. v. §18 All Salts are Angular; with Obtuse, Right, or Acute Angles. 1879 Wright Anim. Life 6 This bone forms an obtuse angle with the pelvis. |
3. fig. Not acutely affecting the senses; indistinctly felt or perceived; dull.
| 1620 Venner Via Recta ii. 31 The wine..carrieth the same, which otherwise is of an obtuse operation, vnto all the parts [of the body]. 1726 Swift To a Lady, Bastings heavy, dry, obtuse. 1790 Crawford in Phil. Trans. LXXX. 426, I..felt an obtuse pain..in my stomach. 1897 Allbutt's Syst. Med. IV. 126 Pain, sharp or obtuse. |
4. Not acutely sensitive or perceptive; dull in feeling or intellect, or exhibiting such dullness; stupid, insensible. (In quot. 1606, Rough, unpolished: = blunt a. 4.)
| 1509 Hawes Past. Pleas. xiii. (Percy Soc.) 113, I am but yonge, it is to me obtuse Of these maters to presume to endyte. 1602 Marston Antonio's Rev. i. iii. Wks. 1856 I. 79, I scorne to retort the obtuse jeast of a foole. 1606 Warner Alb. Eng. xvi. civ. (1612) 408 Obtuse in phrase. 1667 Milton P.L. xi. 541 Thy Senses then Obtuse, all taste of pleasure must foregoe. 1829 Scott Anne of G. ii, Obtuse in his understanding, but kind and faithful in his disposition. 1885 M. Blind Tarantella I. xi. 121 We were too obtuse to understand their peculiar way of manifesting it. |
5. Comb., as obtuse-angled, having an obtuse angle or angles (also obtuse-angular rare—0); also in Nat. Hist., with another adj., expressing a combination of forms, as obtuse-ellipsoid.
| 1660 Barrow Euclid i. Def. xxvii, An Amblygonium, or obtuse-angled Triangle, is that which has one angle obtuse. 1706 Phillips, Obtuse-angled Cone. 1878 A. H. Green, etc. Coal iv. 146 The two types of fin-structure are sometimes distinguished as obtuse-lobate and acute-lobate. 1882 Ogilvie, Obtuse-angular, having obtuse angles. |
▪ II. † obtuse, v. Obs. rare—1.
In 7 erron. obtuce.
[f. obtuse a.]
trans. To blunt, to dull.
| 1618 Hornby Sco. Drunk. (1859) 11 Bacchus, thou god of all ebriety Which dost obtuce and blunt the edge of wit. |