1) Ad lib 2) Ad-lib 3) Array programming language 4) Extemporaneous 5) Extemporary 6) Impromptu 7) Off-hand 8) Offhanded 9) On the spur of the moment 10) Science fiction short story 11) Short story by Damon Knight 12) Spoken off the cuff 13) Unprepared 14) Unrehearsed 15) Without previous preparation 1) Ad-lib 2) Extemporal 3) Extemporaneous 4) Extemporaneously 5) Extemporarily 6) Extemporary 7) Impromptu 8) Offhand 9) Offhanded 10) Unprepared 11) Unrehearsed 
without preparation; offhand
• (adv.) Without previous study or meditation; without preparation; on the spur of the moment; suddenly; extemporaneously; as, to write or speak extempore. • (n.) Speaking or writing done extempore. • (a.) Done or performed extempore.
Ex·tem'po·re adverb [ Latin ex out + tempus , temporis , time. See Temporal .] Without previous study or meditation; without preparation; on the spur of the moment; suddenly; extemporaneously; as, to write or speak extempore . Shak. -- ...
without previous thought or preparation 
An improvised poem e.g. Extempore Effusion upon the Death of James Hogg by Wordsworth. See also impromptu.
extempore With little or no preparation.; literally 'out of the moment'.
on the spur of the moment; without premeditation or preparation; offhand: Questions were asked extempore from the floor. · without notes: to speak extempore. · (of musical performance) by improvisation.