Definition - having a hot head (as from drinking)
The first use of hotheaded was in the sense in which the word is most often encountered today: "fiery, hasty, impetuous."
And although some hott headed Catholickes Romaine will perhappes praise the Popes zeale in deposing of our Princes, yet must they needes all confesse, that it was done smally for the weale of him, & his friendes here, and therefore done without iudgement and discretion.
— John Bishop, A Courteous Conference with the English Catholikes, 1598
Less often found today, although no less worthy of use, is the sense "having a hot head (as from drinking)."
What a damn'd Chicken-brain'd Fellow am I grown? If I but dip my Bill I am giddy. Now am I as hot-headed with my bare two Bottles, as a drunken Prentice on a Holiday.
— Thomas Otway, Friendship in Fashion, 1678