IPA: /ˌɪmprəvaɪˈzətɔːrɪəl/
KK: /ɪmˌprɑːvɪˈzeɪtɔːrɪəl/
Relating to the act of creating or performing something spontaneously without preparation.
The actor's improvisatorial skills impressed everyone during the performance.
Improvisatorial is formed from "improvisare" (meaning to provide or compose on the spot) and the suffix "-orial" (meaning relating to or characterized by). The word refers to something that is related to or characterized by improvisation, particularly in performance or creative contexts.
Think of 'providing' something 'on the spot' — that's what improvisation is about, and the '-orial' part indicates it relates to that spontaneous act.