Gupta-vidya is a Sanskrit term composed of two words:
Gupta derives from the Sanskrit verb gupt which means preserve, while Vidya means knowledge, wisdom.
In the Theosophical tradition this means Secret knowledge, secret wisdom and the source of all known religions and philosophies. Regarded as the ancient religion, wisdom or esoteric philosophy, also known as a synonym for theosophy.
References
Gupta-Vidya Wikipedia(Text) CC BY-SA