English▸ adjective pleased or willing under the circumstances:
the traveler was fain to proceed.
▪ compelled by the circumstances; obliged:
he was fain to acknowledge that the agreement was sacrosanct.
▸ adverb with pleasure; gladly:
I am weary and would fain get a little rest.
– ORIGIN Old English fægen ‘happy, well pleased’, of Germanic origin, from a base meaning ‘rejoice’; related to fawn2.