IMPROVISE v. 2 definitions
To compose, recite, or sing extemporaneously, especially in verse; to extemporize; also, to play upon an instrument, or to act, extemporaneously.
MAGISTRAL a.
Formulated extemporaneously, or for a special case; -- opposed to officinal, and said of prescriptions and medicines. Dunglison. Magistral line (Fort.), the guiding line, or outline, or outline, by which the form of the work is determined. It is usually the crest line of the parapet in fieldworks, or the top line of th…