Done or produced extempore.

Unpremeditated; esp. of prayer, discourse, composition, etc.; = extempore, adv. 2. Occasionally of a speaker; †formerly also of the ability to speak.

Done, performed, or prepared on the spur of the moment; extempore, impromptu. Obsolete.

= extemporaneous, adj.

= extempore, v.

Arising out of the moment; casual, occasional; sudden, unprepared for. Now only of personal actions (cf. A. 2).

Not premeditated or studied, off-hand, extempore; esp. of discourse, prayer, etc. Rarely of a person: Speaking extempore; also, inclined to…

Composed or uttered without preparation or premeditation; improvised; invented, produced, etc. on the spur of the moment and without previous thought.

= C. 1.

Improvised, extemporaneous; unscripted.

Of a performance, speech, etc.: deviating from the given script, or not using a script; improvised, extempore, unscripted. Also figurative.

Of a piece of music: performed, or intended to be performed, in whatever manner the performer pleases. Later more generally: extemporized…