Unknown
Unidentified
noun, な adjective, の adjective
Something is not detailed at all. I don't know anything about it. No details whatsoever. It's a totally unknown entity. It's unidentified.
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
ワニカニは、性別不詳のモンスターです。
Wanikani is a monster whose gender is unknown.
イトコは、ほぼ会わないからステータスが不詳なんだよね。
My cousin's status is unknown because we almost never see each other.
その人物は、年も性別も全てが不詳だった
That person was shrouded in mystery, with their age and gender both unknown.