1. A quick and cheerful readiness to do something: "They prepared for the trip with alacrity."
2. Promptness or eager and speedy readiness to respond to something: "He answered the call for assistance from his supervisor with alacrity."

"Despite his advanced age, he moved with alacrity or agility and nimbleness."

Alacrity is a very good word to describe the readiness and eagerness of the part of someone who is trying for a new job or a challenge. In fact, it would probably be a good idea to describe oneself as having an alacrity for certain projects during the interview for the job.