Ad Hoc, Unannounced Performance
This page is the CodyCross answer for the clue below from Space Exploration, Group 916, Puzzle 5 (Cassiopeia).
Question is: Ad Hoc, Unannounced Performance
and the answer is: IMPROMPTU
Word Meaning:
IMPROMPTU — Improvised; without prior preparation, planning or rehearsal.
Definitions from Wiktionary.