- not known
"an unknown amount"
"an unknown island"
- not known to exist
"things obscurely felt surged up from unknown depths"
- Unknown, unloved.
- Her name was unknown.
- Tom is an unknown artist.
- This is unknown country to me.
- His parentage was unknown to us.
- The meaning is unknown to me.
- The origin of the fire is unknown.
- The reason she killed herself is unknown.
- The cowboys rode into an unknown town.
- The cause of the accident is unknown.
- Smallpox was unknown to Native Americans.
- The cause of the fire was unknown.
- The source of the fire is unknown.
- These things are often unknown to the world.
- The whereabouts of the suspect is still unknown.