\Im*prov"i*sate\, a. [See {Improvise}.]
Unpremeditated; impromptu; extempore. [R.]

\Im*prov"i*sate\, v. t. & i. [imp. & p. p.
{Improvisated}; p. pr. & vb. n. {Improvisating}.]
To improvise; to extemporize.