A visor or mask.
A grotesque vizard. -Sir W. Scott.
There, then, that vizard, that superfluous case, that hid the worse and show'd the better face.-- Shakespeare, Love's Labors Lost V.ii.387
To mislead and betray them under the vizard of law. - John Milton.
Origin of vizard
Alteration of obsolete vizar from Middle English viser visor