Does a Muslim become an unbeliever if, when asked by a disbeliever who claims to be a Muslim—and the Muslim knows of his disbelief—"Am I a Muslim or an unbeliever?" he replies, "I don't know," despite knowing of his disbelief, and does so out of fear of the disbeliever's authority?

This situation is not about refraining from declaring a disbeliever as such; the person knows he is a disbeliever, but fear prevents him from explicitly stating it. In any case, one must advise the one who insults religion and Allah, explain the danger of his action, and clarify that it is an act of disbelief by consensus, whenever possible and safe from harm. Whoever abandons enjoining the evil with the ability to do so, sins; however, his abandonment is not an act of disbelief.