'troglodytism' originates from Greek, specifically the word 'troglodytēs', where 'trōglē' (or 'trogl-') meant 'hole' or 'cave' and 'dytēs' (from 'dyesthai'/'dyein') meant 'one who dives/enters'. The English formation adds the noun-forming suffix '-ism'.

'troglodytēs' passed into Late Latin as 'troglodyta' and then into Old/Middle French as 'troglodyte'; English adopted 'troglodyte' and later formed 'troglodytism' by adding the suffix '-ism' to denote the state or practice.

Initially it referred literally to 'one who lives in caves'; over time it acquired figurative senses — 'reclusive or primitive behavior' — while retaining the literal archaeological sense.