action committee; executive committee
A committee responsible for planning and carrying out events or projects. Often used in school, community, or organizational contexts.
I was chosen for the cultural festival executive committee.
The executive committee will decide the budget at next week's meeting.
実行委員 sounds similar but means a member of an organizing committee for an event, not an executive‑committee member like 執行委員.
Compound of 実行 (じっこう, 'execution') + 委員 (いいん, 'committee member').