Emily Dickinson Lexicon

FAIN, a. [Sax. fagen, fægan, glad; fagnian, Goth. faginon, to rejoice; Sw. fägen. Class Bg, No. 3, 43, 77.]

Glad; pleased; rejoiced. But the appropriate sense of the word is glad or pleased to do something under some kind of necessity; that is, glad to evade evil or secure good. Thus, says Locke, "The learned Castalio was fain to make trenches at Basil, to keep himself from starving." This appropriation of the word, which is modern, led Dr. Johnson into a mistake in defining the word. The proper signification is glad, joyful.