extemporizePronunciation: /ɪkˈstɛmpərʌɪz, ɛk-/ (also extemporise)Definition of extemporize verb [no object] compose or perform something such as music or a speech without preparation; improvise:he extemporized at the piano [with object]:she was extemporizing touching melodiesDerivatives extemporizationPronunciation: /-ˈzeɪʃ(ə)n/ noun extemporize in other Oxford dictionaries Definition of extemporize in the US English dictionary