ἐγγώνιος
From LSJ
ἔγνω δὲ φώρ τε φῶρα καὶ λύκος λύκον → the thief knows the thief and the wolf knows the wolf, and thief knows thief and wolf his fellow wolf, set a thief to catch a thief
English (LSJ)
ον, (γωνία)
A forming an angle, esp. right angle, σχῆμα Hp.Art.22; λίθοι ἐντομῇ ἐγγώνιοι cut square, Th.1.93; πύργοι J.BJ 7.8.3. Adv. -ίως Paul.Aeg.6.115. II cut into angles, of ivyleaves, Thphr.HP3.15.4 (Comp.).
German (Pape)
[Seite 702] einen Winkel bildend; λίθοι ἐν τομῇ ἐγγώνιοι, winkelrecht zugehauen, Thuc. 1, 93; Hippocr. u. Sp.