'extemporize' originates from Latin, specifically the word 'extemporaneus,' where 'ex-' meant 'out of' and 'tempus' meant 'time.'

'extemporaneus' transformed into the French word 'extemporiser,' and eventually became the modern English word 'extemporize' through Middle English.

Initially, it meant 'out of time,' but over time it evolved into its current meaning of 'to improvise or perform without preparation.'