What is another word for black-box?
Pronunciation: [blˈakbˈɒks] (IPA) 
The term "black-box" refers to an object or system whose internal workings are unknown or opaque. Common synonyms for black-box include opaque, mysterious, enigmatic, and inscrutable. These words all suggest a lack of transparency and a complexity that is difficult to understand. Other possible synonyms might include impenetrable, unexamined, or unintelligible. These words all suggest a state of unknowability, and they can be applied to a wide range of objects and systems, from technical devices to social institutions. Ultimately, the term "black-box" and its synonyms are useful for describing anything that is difficult or impossible to fully understand.
