有志|ゆうしyuushi[1]atamadaka (head-high)

1. no-adjectiveinterested person; volunteer; supporter
   その協会きょうかいは有志ゆうしを求もとめる広告こうこくをテレビに出だした。↗

   The institution advertised on TV for volunteers.

• Synonym有志者WrittenFormal written term that plainly says 'a person with resolve'. 「有志」 itself already refers to a person, as in 「有志一同」, so it usually suffices.
• Antonym無関心むかんしんNeutralNeutral word for apathy or indifference; it stands opposite 「有志」, which implies a willingness to get involved.

Use 「有志」 for people willing to take part, as in 「有志を募る」 or 「有志一同」; it already denotes the people themselves. 「有志者」 is a formal written variant, and 「無関心」 is the opposite — indifference.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. ある物事ものごとに関心かんしんをもち、関かかわろうとする意志いしのあること。また、その人ひと。