Webster's Revised Unabridged Dictionary · 1913

Fain

Fain , adjective

[Old English fain, fagen, Anglo-Saxon fagen; akin to Old Saxon fagan, Icelandic faginn glad; Anglo-Saxon fagnian to rejoice, Old Saxon faganōn, Icelandic fagna, Gothic faginōn, compare Gothic fahēds joy; and from the same root as English fair. Srr Fair, a., and compare Fawn to court favor.]

1.
Well-pleased; glad; apt; wont; fond; inclined.
Men and birds are fain of climbing high. — Shakespeare
To a busy man, temptation is fainto climb up together with his business. — Jer. Taylor
2.
Satisfied; contented; also, constrained. — Shakespeare
The learned Castalio was fain to make trechers at Basle to keep himself from starving. — Locke

Fain , adverb

With joy; gladly; -- with wold.
He would fain have filled his belly with the husks that the swine did eat. — Luke xv. 16
Fain Would I woo her, yet I dare not. — Shakespeare

Fain , verb, transitive and intransitive

To be glad; to wish or desire. [Obsolete]
Whoso fair thing does fain to see. — Spencer