unaccountable
un-ac-count-a-ble
adjective
Not required to explain or justify one's actions or decisions.
"The minister was unaccountable for his department's failures."
adjective
Unable to be explained or understood; mysterious or baffling.
"There was an unaccountable silence in the usually busy street."
Thesaurus
Synonyms: unexplainable, incomprehensible, inexplicable, irresponsible