The word "troglodyte" originates from Ancient Greek, meaning "one who dwells in holes."   It's formed by combining "trogl-" (from "trṓglē," meaning "hole") and "dy-" (from "dýein," meaning "to creep into"). The suffix "-tēs" indicates an agent or someone who performs the action.   It came to English via Latin from Greek trōglodutēs, alteration of the name of an Ethiopian people, influenced by trōglē ‘hole’.

The term was first used in the 16th century to describe cave-dwelling people, and later expanded to describe those with outmoded or reactionary attitudes.  The first recorded use of the word "troglodyte" in English was in the mid-1500s, specifically around 1555.  The Oxford English Dictionary lists an example of its use in a translation by William Waterman from that year. 

Examples of "troglodyte" used in a sentence: 
"The villa was turned into a motte in the 10th century, around which the village developed, in part in excavated troglodyte dwellings." 
"He could feel himself slowly melting into the kind of troglodyte you sometimes saw scurrying off the end of the subway platform." 
"Soldiers on both sides lived a desperate troglodyte existence in the waterlogged shell holes that had destroyed almost all trace of their trench systems." 
"In the vicinity are the troglodyte caverns of Monte Scaglioso, still inhabited by some of the lower classes, and other caves with 13thcentury frescoes."

There are cave dwellings still inhabited in a nearby town, Paterna, which featured in an Almodóvar film with Penelope Cruz! “”Dolor y Gloria” 2019.  The “casa-cuevas” as they are called here play an important role in the film.  

Just the facts:

TROGLODYTE Definition & Meaning - Merriam-Webster