speak off the cuff

extemporize invent

make up speak extemporaneously speak impromptu

plan prepare rehearse write

ad-lib brainstorm concoct contrive devise dream up invent throw together

coin extemporize fake jam spark

dash off do off top of head do offhand fake it improv improvisate made do wing it

design plan premeditate

ad-lib concoct devise do off the top of your head do offhand fake it improv invent make do make up play it by ear throw together