Svecchachara is the Sanskrit equivalent of the Greek word Thelema.
In the first volume of the TWILIGHT YOGA, Ecstasy, Equipoise, and Eternity, Shri Gurudev Mahendranath wrote,
Sveccha means one's own wish or free will. Svecchachara means a way of life where one acts as one wishes and does what is right in one's own eyes. Doing one's own Will. The concluding Sanskrit expression in the Avadhoota Upanishad is "Svecchachara Paro."
The term "Paro" means a mysterious or secret pattern to that action done by one's own Will. In other words, we do our Will but with discretion, not making it too obvious, nor to harm or hurt other people. Yet this is also a typical Nathism; a complete reversal of Vedic morals and philosophy.
Mahendranath, Shri Gurudev. Ecstacy, Equipoise, and Eternity (http://www.mahendranath.org/twiyoga1.mhtml). Retrieved Oct. 15, 2004.