The phrase "secret sect" refers to a group or organization that operates secretly, often with their activities and beliefs kept hidden from the public. Full definition
The Librarians Season 4 (2017) A secret sect of the Vatican Church unearths a map detailing the locations of the four cornerstones of the Library of (myintimcity.com)
Indeed, the profligacy of secret sects represents the ever increasing threat of apocalyptic meltdown to mainline sects.Rumour has it that it's proponents prefer some mysterious new floss call G - String Theory to more traditional methods of exorcising the forbidden fruit. (nakedpastor.com)
We are most impressive when operating as a secret sect, kneeling in small, candle - lit rooms and scrawling fishes on walls.» (premierchristianity.com)