Definition of: improvise

(im′prə·vīz) v.t. & v.i. ·vised, ·vis·ing
1. To compose, recite, sing, etc., without previous preparation; extemporize.
2. To make or devise on the spur of the moment, especially from what is at hand: to improvise a raft from driftwood. Also im·prov′i·sate (im·prov′ə·zāt). [<F improviser <Ital. improvvisare <improvviso unforeseen <L improvisus <in- not + provisus foreseen]
—im·prov·i·sa·tion (im·prov′ə·zā′shən, im′prə·vī·zā′shən) noun
—im′pro·vis′er, im·prov′i·sa′tor noun
—im·prov·i·sa·to·ri·al (im·prov′ə·zə·tôr′ē·əl, -tō′rē·əl), im·prov′i·sa·to′ry (-tôr′ē, -tō′rē) adjective