improvise
v.to create or perform something without preparing it first. You use this when you have to make a plan or a speech at the last minute.
v.to compose, perform, or deliver without prior preparation; to produce something using whatever materials are available at the moment.
“I forgot my notes, so I had to improvise the speech.”
“When the power went out during the dinner party, we had to improvise and eat by candlelight.”
“The jazz musicians began to improvise over the basic chord progression, creating a complex and spontaneous melody that captivated the entire audience.”
Can be used transitively (to improvise a solution) or intransitively (to improvise during a performance).
“It has more than 40 speaking characters, voiced by Australian comedians who perform the written dialogue before improvising alternative takes.”
“Rohmer employed a skeleton crew and encouraged his cast to improvise, ensuring that his film remained unencumbered and almost weightless, open to the world’s possibilities and the happy accidents it might send our way.”
From French improviser; ultimately from Latin improvisus.
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.