Synonyms: unexplained
Definition: having the reason or cause not made clear
Usage: an unexplained error
Similar words: inexplicable, incomprehensible
Definition: incapable of being explained or accounted for
Usage: inexplicable errors; left the house at three in the morning for inexplicable reasons
Synonyms: unexplained
Definition: not explained
Usage: accomplished by some unexplained process
Similar words: undetermined
Definition: not yet having been ascertained or determined
Usage: of undetermined species