Definition - What does Siddha Shaivism mean?
Siddha Shaivism is the name given to both the texts and a yogi who believes in and practices the philosophy of the ancient school of Saivism or Shaivism. Siddha is a Sanskrit word meaning, "one who is proficient in," and Shaivism is the name of the ancient traditions and practices of yogis who believe that Lord Shiva is the Brahman, or Supreme Self, and who worship Lord Shiva.
Yogapedia explains Siddha Shaivism
Practiced in the Indus Valley civilization in 5000 B.C.E., Shaivism is believed to have begun even earlier. A Siddha-Shaivism would have been a devout practitioner of Shaivism who had a deep practice and who understood the rituals and traditions that must be followed. Shaivism texts include; the Vedas, the twenty-eight Hindi Agamas and the "Tirumurai," the twelve books of the Tamil Saiva.
Mostly practiced today by Hindus and Tamils in Southern India and Sri Lanka, where there are temples and monasteries, Shaivism is a monotheistic practice, celebrating Lord Shiva. Siddha Shaivism refers to both the texts and those yogis who have studied the texts and are able to understand them. The title can be given to monks and teachers as well as deserving practitioners.