inexplicable
in-ex-pli-ca-ble
adjective
Unable to be explained or understood, often because it is very strange.
"The sudden power cut was completely inexplicable."
Thesaurus
Synonyms: unexplained, cryptic, deep, paradoxical, mysterious, self-contradictory, unexplainable, mystifying, inscrutable, cryptical, incomprehensible, unaccountable
Antonyms: explicable