Word to the Wise: Extempore

Something that’s "extempore" (ik-STEM-puh-ree) - Latin for "out of the time" - is done on the spur of the moment, without preparation.

Example (as used by Robert Harris in Archangel: "Kelso had already delivered his short paper… at the end of the previous day: delivered it in his trademark style - without notes, with one hand in his pocket, extempore, provocative."