Slowly, without haste, as in the famous 16th-century proverb, Marry in haste and repent at leisure.
Unemployed, having free time, as in I'm not looking for another job right now; I want to be at leisure for at least a few months. This usage has become less common but is still heard. [1300s] Also see at one's leisure.
Dictionary.com presents 366 FAQs, incorporating some of the frequently asked questions from the past with newer queries.