- 1unknown (to somebody) not known or identified a species of insect previously unknown to science He was trying, for some unknown reason, to count the stars. The man's identity remains unknown.
- 2(of people) not famous or well known an unknown actor The author is virtually unknown outside Poland.
- 3never happening or existing The disease is as yet unknown in Europe (= there have been no cases there). It was not unknown for people to have to wait several hours (= it happened sometimes). Idioms
a person or thing whose qualities or abilities are not yet known
without the person mentioned being aware of it Unknown to me, he had already signed the agreement.
Check pronunciation: unknown