Obscurantism (French: obscurantisme, from the Latin obscurans, “darkening”) is the practice of deliberately preventing the facts or the full details of some matter from becoming known. There are two, common, historical and intellectual, denotations: 1) restricting knowledge—opposition to the spread of knowledge, a policy of withholding knowledge from the public, and, 2) deliberate obscurity—an abstruse style (as in literature and art) characterized by deliberate vagueness.

The term obscurantism derives from the title of the 16th-century satire Epistolæ Obscurorum Virorum (Letters of Obscure Men), based upon the intellectual dispute between the German humanist Johann Reuchlin and Dominican monks, such as Johannes Pfefferkorn, about whether or not all Jewish books should be burned as un-Christian. Earlier, in 1509, the monk Pfefferkorn had obtained permission from Maximilian I (1486–1519), the Holy Roman Emperor, to incinerate all copies of the Talmud (Jewish law and Jewish ethics) known to be in the Holy Roman Empire; the Letters of Obscure Men satirized the Dominican monks' arguments for burning “un-Christian” works.