Definition of "quoif"

A scaly gauntlet now with joints of steel / Must glove this hand: and hence, thou sickly quoif! / Thou art a guard too wanton for the head / Which princes, flesh'd with conquest, aim to hit.

c. 1596–1599 (date written), William Shakespeare, “The Second Part of Henry the Fourth, […]”, in Mr. William Shakespeares Comedies, Histories, & Tragedies […] (First Folio), London: […] Isaac Iaggard, and Ed[ward] Blount, published 1623, (please specify the act number in uppercase Roman numerals, and the scene number in lowercase Roman numerals)