The OED says that perfervid, with the meaning of “very fervid, glowing, or ardent,” is a new word for English, one unseen in print before the latter have of the 19th century. Here are some of its citations from the OED:
- 1856 Masson Ess., Scot. Infl. Brit. Lit. 395 ― Without maintaining at present that all Scotchmen are perfervid··it will be enough to refer to the instances which prove at least that some Scotchmen have this character.
- 1875 Helps Soc. Press. xxii. 339 ― The next generation has something in it of the brilliant nature of the Irish, or the perfervid nature of the Scotch.
- 1884 Howells in Harper’s Mag. Dec. 115/2 ― With perfervid gratitude.
Derived forms include:
Hence perferˈvidity, perˈfervidness, also ˈperfervour, perfervid quality.
- 1861 J. Brown Horæ Subs. Ser. ii. 425 ― This perfervor of our Scottish love-songs.
- 1884 Sat. Rev. 1 Nov. 559/2 ― We are disposed to regret these manifestations and consequences of the perfervidity of Birmingham.
- 1890 Spectator 4 Oct., ― The characteristic of the Scotchman is perfervidness, exhibiting itself in strenuosity, in enthusiasm, and in excess.
I rather like perfervor from 1861; it reminds me of Spanish por favor. :)
Perfervid derives from Latin, but “modern” rather than classical Latin:
Etymology: ad. mod.L. perfervid-us, f. per- 4 + fervidus fervid; chiefly in the phrase perfervidum ingenium Scotorum, founded on Buchanan’s Scotorum præfervida ingenia (Rerum Scotic. Hist. XVI. li.). Perfervidus, though quite regular in form, is not recorded in ancient Latin; an instance of perfervida formerly cited from Columella v. 5 is an erroneous reading in Gesner’s ed. (1737) for præfervida.