Alacrity

A*lac"ri*ty (?), n. [L. alacritas, fr. alacer lively, eager, prob. akin to Gr. ? to drive, Goth. aljan zeal.] A cheerful readiness, willingness, or promptitude; joyous activity; briskness; sprightliness; as, the soldiers advanced with alacrity to meet the enemy.

I have not that alacrity of spirit,
Nor cheer of mind that I was wont to have.
Shak.