troglodyte

noun

1. A member of a supposed prehistoric race that lived in caves or holes, a caveman.
2. (broadly)Anything that lives underground.

   “The cave was populated by albino scorpions, blind salamanders, and other troglodytes.”

   “Inhabited as early as the Gallo-Roman era, the caves of the troglodytes are slighted in guidebooks, naturally overshadowed by the chateaus of the kings.”

3. The Eurasian wren, Troglodytes troglodytes.
4. (derogatory)A reclusive, reactionary or out-of-date person, especially if brutish.

   “Blair brought out the febrile intensity of Stanhope, wiring himself into his ever more circumscribed troglodyte world, speculating moodily on the worm that went down when it thought it was coming up. Robert Philp thought Blair's ...”

5. A person who chooses not to keep up to date with the latest software and hardware.