In the manner of a conventicle; in a secretive, unauthorized, or clandestine religious gathering way.
From 'conventical' plus '-ly' adverbial suffix. Creates an adverb describing actions done in the style of secret religious assemblies.
Puritan separatists in 17th-century England met 'conventically' in hidden homes and forests, risking imprisonment for worshiping without the Church of England's approval!
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