Webster’s Revised Unabridged Dictionary · 1913
Extemporaneous
Ex·tem′po·ra′ne·ous (·ŭs), a. [See Extempore.] Composed, performed, or uttered on the spur of the moment, or without previous study; unpremeditated; off-hand; extempore; extemporary; as, an extemporaneous address or production. — Ex·tem′po·ra′ne·ous·ly, adv. — Ex·tem′po·ra′ne·ous·ness,n.