noun
full-time trade union official
A person who works full-time for a labor union, often while on leave from their regular job.
彼は組合専従者として、労働条件の改善に取り組んでいる。
As a full-time union official, he is working to improve working conditions.
組合員 is a general union member, while 組合専従者 is a full-time union staff member.
Compound of 組合 (union) + 専従 (full-time service) + 者 (person).