a. Forms: 4 tricherous, -ows; 4–7 trecherous, (4–5 -us, 5 -owse, treccherous, 6 trechrous, 7 tretcherous), 6– treacherous, (6 -ouse). [a. OF. trecher-, tricheros, -us, -eus (12th c. in Godef.), f. trecheur, tricheur TREACHER: see -OUS.]
1. Of persons, their attributes or actions: Characterized by treachery; deceiving, perfidious, false; disloyal, traitorous.
c. 1330. R. Brunne, Chron. Wace (Rolls), 16519. Þe tricherous Saxons—Þeyr tricherye vs euere mones.
1387. Trevisa, Higden (Rolls), I. 357. Þe men beeþ variable and vnstedefast, trecherous and gileful.
1483. Cath. Angl., 392/1. Trecherus, vbi fals (A.).
1570. Levins, Manip., 226/34. Treacherouse, proditorius.
1611. Shaks., Cymb., IV. ii. 317. To write, and read, Be henceforth treacherous.
1644. Evelyn, Diary, 17 Nov. After a true tretcherous Italian guise.
1725. De Foe, Voy. round World (1840), 91. As fierce cruel treacherous and merciless a crew of human devils as any I have met with.
1897. Mary Kingsley, W. Africa, 329. A treacherous, thievish, murderous cannibal.
2. fig. Of things: Deceptive, untrustworthy, unreliable; of ground, ice, etc., unstable, insecure.
1610. B. Jonson, Alch., II. iii. O, yes, but I forgot. I haue … One o’ the treacherou’st memories, I doe thinke, Of all mankind.
1709. Pope, Ess. Crit., 492. The treach’rous colours the fair art betray, And all the bright creation fades away.
1806–7. J. Beresford, Miseries Hum. Life (1826), II. v. The ice proving treacherous.
1855. Macaulay, Hist. Eng., xiii. III. 335. Up steep crags, and over treacherous morasses, he moved as easily [etc.].
1860. Tyndall, Glac., I. xv. 102. Over other [crevasses] a thin and treacherous roof was thrown.
1901. Alldridge, Sherbro, xxvi. 288. By and by we scrambled over a treacherous-looking bamboo bridge.
