from E-NED: from medieval Latin honōrificābilitūdinitās (Mussatus c 1300 in Du Cange), a grandiose extension of honōrificābilitūdo honourableness (in a charter of 1187, Du Cange), from honōrificābilis honourable.
Cf. Complaynt of Scotland (1548–9), Prolog. lf. 14 b, Shakes. L.L.L. v. i. 44, and Marston Dutch Courtezan v. (1605) H, where the Latin abl. pl.honōrificābilitūdinitātibus is cited as a typical long word, as honōrificābilitūdinitāte had been previously by Dante De Vulg. Eloq. ii. vii
(1599 - Nashes Lenten Stuffe - see below from E-NED)
1656 - Glossographia, Thomas Blount
From: The Universal Magazine
Containing Original Communications in History, Philosophy, the Belles Lettres,
Politics, Amusements, &c. &c.
Volume III, January to June, Inclusive, 1805
From: The Bee-Hive, A Musical Farce
By Charles Edward Horn, John Gideon Millingen, Pigault-Lebrun, 1811
Overture and Music Composed By Mr. Horn
Act II, Scene I