(1):
(n.) One of those (as in the 16th century) who denied the visibility of the church.
(2):
(a.) Incapable of being seen; not perceptible by vision; not visible.
(3):
(n.) An invisible person or thing; specifically, God, the Supreme Being.
(4):
(n.) A Rosicrucian; - so called because avoiding declaration of his craft.