(1):

(n.) Customary way of speaking or acting; custom; fashion; manner; behavior; mien; mode; practice; - often used formerly in such phrases as: at his own guise; that is, in his own fashion, to suit himself.

(2):

(n.) External appearance in manner or dress; appropriate indication or expression; garb; shape.

(3):

(n.) Cover; cloak; as, under the guise of patriotism.