The Nambudiri Brahmins also transliterated Namboothiri are Hindu

Hindu

Hindu refers to an identity associated with the philosophical, religious and cultural systems that are indigenous to the Indian subcontinent. As used in the Constitution of India, the word "Hindu" is also attributed to all persons professing any Indian religion...

 Brahmins from the Indian state of Kerala.

They perform rituals in temples of Kerala based on Tantra Vidhi, a complex and ancient branch of Tantric

Tantra

Tantra , anglicised tantricism or tantrism or tantram, is the name scholars give to an inter-religious spiritual movement that arose in medieval India, expressed in scriptures ....

 traditions found only in Kerala and some Mahakshetras ("Great Temples") around India that have a Nambudiri as head priest.

Nambudiris follow the conservative and ritualistic Śrauta

Srauta

' traditions are conservative ritualistic traditions of the historical Vedic religion in Hinduism, based on the body of Śruti literature...

 traditions and the ancient Mimāṃsā

Mimamsa

' , a Sanskrit word meaning "investigation" , is the name of an astika school of Hindu philosophy whose primary enquiry is into the nature of dharma based on close hermeneutics of the Vedas...

, unlike the majority of other Brahmins in India, who follow the Vedanta

Vedanta

Vedānta was originally a word used in Hindu philosophy as a synonym for that part of the Veda texts known also as the Upanishads. The name is a morphophonological form of Veda-anta = "Veda-end" = "the appendix to the Vedic hymns." It is also speculated that "Vedānta" means "the purpose or goal...

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