Describes something that everybody simply accepts — nobody has argued with it, challenged it, or asked whether it is right. Two flavours, and they feel quite different. The first is admiring: his unquestioned authority, her unquestioned place as the leader, the unquestioned champion. Here it means the person's position is so secure that no one bothers to contest it. The second is cooler, almost critical: an unquestioned assumption, unquestioned tradition, unquestioned belief. Here the writer is often hinting that people SHOULD have asked questions and did not — the idea has simply been passed along and swallowed. Which flavour you get depends on the noun that follows and on the writer's attitude, so read the sentence around it. Compare it with 'unquestionable'. 'Unquestionable' means the thing could not be doubted; 'unquestioned' only means it has not been doubted — which leaves room for the possibility that it is wrong and nobody noticed. That gap between 'cannot be' and 'has not been' is the whole difference, and it is worth holding on to. It also has a plain, literal use: if your story goes unquestioned, nobody asked you about it. Police and customs officers 'let someone pass unquestioned'.