ALACRITY
alacrity, briskness, smartness
(noun) liveliness and eagerness; “he accepted with alacrity”; “the smartness of the pace soon exhausted him”
Source: WordNet® 3.1
Etymology
Noun
alacrity (countable and uncountable, plural alacrities)
Eagerness; liveliness; enthusiasm.
Synonyms: avidity, eagerness, enthusiasm, willingness
Antonyms: apathy, disinclination, hesitance, indifference, reluctance
Promptness; speed.
Synonyms: briskness, celerity, haste, promptness, quickness, swiftness
Source: Wiktionary
A*lac"ri*ty, n. Etym: [L. alacritas, fr. alacer lively, eager, prob.
akin to Gr. aljan zeal.]
Definition: 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.
Source: Webster’s Unabridged Dictionary 1913 Edition