Green’s Dictionary of Slang

1. a swaggerer, a blusterer [the bully sets his cap at a swaggering angle].

1597		J. Hall Virgidemiarum (1599) Bk I 12: The stalking steps of his great personage, Graced with huf-cap terms, and thundering threats.
1607		Marston What you will III i: Me thinkes I see a huff-cap swaggering, sir.
1630		J. Taylor ‘Sir Gregory Nonsense’ in Works (1869) II 3: But ’tis a Maxime Mortals cannot hinder, / The doughty deeds of wakefields huffe cap Pindar.
1687		M. Clifford Notes upon Mr Dryden’s Poems 7: Was not this Huff-cap once the Indian Emperour, and at another time did not he call himself Maximine?
1706		Farquhar Recruiting Officer V v: You have made a fine speech, good Captain Huffcap.

2. (also huffcap ale, ...liquor) a form of strong ale.

1576		U. Fulwell Art of Flattery 6th dialogue 27: Well Pierce, [...] I trow we shal finde some shift or other to quenche the scorching heat of our parched throates, with the best nippitate in this towne, which is commonly called hufcap.
1587		W. Harrison Description of England 150: There is such headie ale [...] commonlie called huffe-cappe, the mad dog, [...] stride-wide, and lift-leg.
1594		Greene Looking-Glass for London and England in Dyce (1861) 127: [The] ale is strong ale, ’tis huffcap.
1599		Nashe Praise of the Red Herring 74: The huffe-cappest drink in that house you shal be sure of alwayes.
1602		T. Campion Eng. Poesy in Bullen Works (1889) 247: Hunks detests when huffcap ale he tipples [F&H].
1630		J. Taylor ‘Anagrams & Satyrs’ in Works (1869) II 261: Wine-marchants, Vintners, Brewers [...] Whose sale of hufcap liquor doe professe.
1635		J. Taylor ‘Life of Thomas Parr’ in Works (1870) 20: Else hee had little leasure Time to waste, / Or (at the Alehouse) huffe-cap Ale to taste.
1822		R. Nares Gloss. (1888) I 436: huffcap. A cant term for strong ale; from inducing people to set their caps in a bold and huffing style.
1866		Mansfield School-Life at Winchester College (1870) 180: Washed down by libations of ‘Huff’.