participant noun
ADJ. full | active | unwilling, willing She was an unwilling participant in his downfall. | key, leading, main, major | course | conference, seminar
VERB + PARTICIPANT attract Protests on 12 April attracted 100,000 participants.
PARTICIPANT + VERB attend sth
PREP. ~ in an active participant in the discussion
You can also check other dicts: participant (English, 中文解释 ), wordnet sense, Collins Definition