flippant

adjective3

1. •
   Showing disrespect through a casual attitude, levity, and a lack of due seriousness; pert.

   • The conversations had grown more adult over the years—she was less flippant, at least. — 1998
2. •
   (dialect) Nimble; limber.
3. •
   (no longer used) Loquacious; speaking with ease and rapidity.

   • November 5, 1673, Isaac Barrow, sermon on the Gunpowder Treason It becometh good men, in such cases, to be pleasantly flippant and free in their speech.