Definition - What does Tamil Siddha mean?
Tamil siddha is an unorthodox religious philosophy in the traditions of India that is associated with mysticism. The word siddha derives from the Sanskrit root sidh, meaning “being accomplished or fulfilled.” Based in southern India, Tamil siddha is part of a larger siddha movement throughout South Asia and tantric yoga. The siddha movement crosses religious lines with Hindu, Buddhist and Jain siddhas sharing similar practices, beliefs about the universe and symbols.
Tamil siddhas trace their origins to the 8th century. Siddhars in Tamil are saints, celestial beings or yogis who have transcended time and space via meditation.
Yogapedia explains Tamil Siddha
The Tamil siddha philosophy is based on portions of the religious text "Tirumantiram," particularly the part called the "Tantrasastra," which describes Shakti worship, chakras and magic spells. Shiva is the supreme god and Ultimate Reality, but to Tamil siddhas, the goddess Shakti, the feminine aspect of Shiva, is preeminent. Shakti is the divine force or life-force energy within the body and is, therefore, more accessible than Shiva.
Through mysticism and yogic practices, Tamil siddhas manipulate the flow of the goddess energy throughout the body to reach the ultimate goal of union with the Absolute and the highest consciousness. Siddhas avoid temple worship and do not believe in the authority of the Brahmin priestly class.