1.
outsider; third party; unauthorized person
A person who does not belong to a particular group, organization, or area, and therefore has no right to be involved or to enter.
部外者の立ち入りは禁止です。
Entry by unauthorized persons is prohibited.
この問題に部外者は口を出すべきではない。
Outsiders should not interfere in this matter.
会議には部外者が入れないように、セキュリティを強化した。
Security was tightened so that outsiders could not enter the meeting.
USAGE:
部外者 literally means "person outside the department/section." It is commonly used on signs restricting access and in discussions about who has the right to be involved in a matter.
COMMON COLLOCATIONS:
- 部外者立入禁止 (no unauthorized entry)
- 部外者お断り (outsiders not welcome)
- 部外者を排除する (to exclude outsiders)
SIMILAR WORDS:
第三者 (third party) is more neutral and legal, while 部外者 emphasizes not belonging to the group in question. よそ者 (stranger, outsider) is more colloquial.