Etymology: < aguise v. Compare earlier guise n., disguise n.In the spelling with -gg- perhaps by association with formations in classical Latin ag- , variant of ad- ad- prefix (compare note at that entry). The following was presented by N.E.D. (1884) as an earlier instance of this word:?c1475 Catholicon Anglicum (BL Add. 15562) f. 1^v Aguice [1483 BL Add. 89074 Anguice], jndula.However, the forms in question seem ultimately to have arisen from misreading (perhaps by minim confusion) of Anglo-Norman agnice tag, thong, strip appending a seal or schedule to a document, schedule appended to a document (13th cent. as agnyz glossing post-classical Latin indula, or earlier; also as hangnis, agniz, etc.), of uncertain origin; compare also the Anglo-Norman form anguiz (13th cent.), apparently arising by similar minim confusion.

Etymology: Origin uncertain; probably < either a- prefix² or a- prefix³ + guise v. (although no earlier parallels with either y- prefix or on- prefix are attested). Compare earlier disguise v. and later aguise n.