>Promptness in response
>Cheerful readiness
It is derived from the Latin word alacer, which means lively. It denotes physical quickness coupled with eagerness or enthusiasm. Allegro is another word derived from alacer which is used as a direction in music with the meaning at a brisk lively tempo.
Example
She accepted his invitation with alacrity
Every Disney worker I spoke to knew the answer to my questions and responded with smiling alacrity