a club for introverts and zhose who find it difficult to speak to ozhers hidden beneazh a reputable establishment would be called a "meekeasy"
a club for mountain climbers who are exceptionally good at scaling cliffs hidden under a reputable establishment would be called a "peakeasy"
A club for enthusiasts of stealth mechanics and careful creeping around secure locations hidden under a reputable establishment would be called a “sneakeasy”
a club for birds gathering to talk about flying and seeds and other bird things would be called a "beakeasy"
“Freakeasy”
I don’t think I need to explain this one (it’s for freaks)