IPA: /ɪkˈstɛmpəˌrɛri/
KK: /ɛkˈstɛmpəˌrɛri/
Done or spoken without preparation, often in a spontaneous manner.
He gave an extemporary speech that impressed everyone in the audience.
Extemporary → It is formed from "ex-" (meaning out of or from) and "temporarius" (from Latin, meaning temporary or of time). The word describes something that is done out of the moment or without preparation, relating to time.
Think of something that is done 'out of' ('ex-') the moment, which helps you remember that 'extemporary' refers to actions taken without prior planning.