Hindu atheism or Hindu non-theism, which is known as Nirīśvaravāda (Sanskrit: Sanskrit: निरीश्वर्वाद, romanized: nirīśvarvāda, lit. 'Argument against the existence of Ishvara') has been a historically propounded viewpoint in many of the Āstika (Orthodox) streams of Hindu philosophy. Hindu spiritual atheists, agnostics or non-theists who affirm the sanctity of the Vedas and the concept of Brahman, as well as those who follow āstika (orthodox) philosophies but reject personal god(s), are also called Dharmic atheists, Vedic atheists or Sanatani atheists.
In current Indian languages, such as Hindi or Bengali, āstika and its derivatives usually mean 'theist', and nāstika and its derivatives denote an 'atheist'; however, the two terms in ancient- and medieval-era Sanskrit literature do not refer to 'theism' or 'atheism'. In ancient India, āstika meant those who affirmed the sanctity of the Vedas, ātman and Brahman, while nāstika, by contrast, are those who deny all the aforementioned definitions of āstika; they do not believe in the existence of self or Ishvara (God) and reject the sanctity of the Vedas.