troglodyte

Concise Oxford English Dictionary © 2008 Oxford University Press:
troglodyte /ˈtrɒglədʌɪt/

▶noun

• 1 a cave-dweller, especially a primitive or prehistoric one.

• 2 a person who is deliberately ignorant or old-fashioned.

– derivatives
troglodytic /-ˈdɪtɪk/ adjective,
troglodytism noun.

– origin C15: via L. from Gk trōglodutēs, alt. of the name of an Ethiopian people, influenced by trōglē ‘hole’.