Definitions for "Unexplained"
To present participles which come from intransitive verbs, or are themselves employed as adjectives, to mark the absence of the activity, disposition, or condition implied by the participle;
not explained; "accomplished by some unexplained process"
Keywords:  clear, error, cause, reason, percent
having the reason or cause not made clear; "an unexplained error"
No clear cause can be found in up to 10 percent of cases.