unexplained
adjectiveUK /ˌʌnɪkˈspleɪnd/
US /ˌʌnɪkˈspleɪnd/
Something unexplained is something that no one can tell you the reason for.
The strange noise in the attic was never explained.
OTHER MEANINGS
2. Not made clear or understood by anyone.
The unexplained rules confused all the new players.
3. Not given a reason or excuse.
His unexplained absence worried his friends.
4. Not described or accounted for in an official way.
The report listed several unexplained payments.