a person who lives in self-imposed isolation or seclusion from the world, especially for religious purposes; a hermit
a brown recluse spider
A reclusive, reactionary or out-of-date person, especially if brutish.
A person who chooses not to keep up-to-date with the latest software and hardware.
Anything that lives underground.
The Eurasian wren, Troglodytes troglodytes.
A member of a supposed prehistoric race that lived in caves or holes, a caveman.