IPA: /ɛkˈstɛmpəraɪzər/
KK: /ɛkˈstɛmpəraɪzər/
A person who speaks or performs without preparation, often improvising their words or actions.
The extemporizer captivated the audience with his spontaneous speech.
Extemporizer → It is formed from "ex-" (meaning out of or from) and "temporarius" (from Latin, meaning temporary or for a time). The word refers to someone who speaks or performs without preparation, essentially drawing from their immediate resources or thoughts.
Think of someone who is speaking 'out of' ('ex-') their 'temporary' ('temporarius') thoughts — that's why an extemporizer is someone who performs without prior preparation.