noun
nonparticipation; nonattendance
Used for not taking part in an event, meeting, class, or activity. Often appears in formal or written contexts.
彼は会議に不参加だった。
He did not attend the meeting.
不参加の場合は事前に連絡してください。
Please contact us in advance if you will not be participating.
Compound of 不 (negative prefix) and 参加 (participation).