"deprive of inhabitants," 1540s; see de- + populate. Perhaps from Latin depopulatus, past participle of depopulari "to lay waste, ravage." Related: Depopulated; depopulating. Earlier in same sense was dispeplen (early 15c.).
active word-forming element in English and in many verbs inherited from French and Latin, from Latin de "down, down from, from, off; concerning" (see de), also used as a prefix in Latin, usually meaning "down, off, away, from among, down from," but also "down to the bottom, totally" hence "completely" (intensive or completive), which is its sense in many English words.
As a Latin prefix it also had the function of undoing or reversing a verb's action, and hence it came to be used as a pure privative — "not, do the opposite of, undo" — which is its primary function as a living prefix in English, as in defrost (1895), defuse (1943), de-escalate (1964), etc. In some cases, a reduced form of dis-.
"to people, inhabit; form or furnish the population of a country, etc.," 1610s, from Medieval Latin populatus, past participle of populare "inhabit, to people," from Latin populus "inhabitants, people, nation" (see people (n.)). Earlier in English it was an adjective, "peopled, populated" (1570s). Related: Populated; populating.
<a href="https://www.etymonline.com/word/depopulate">Etymology of depopulate by etymonline</a>
Harper, D. (n.d.). Etymology of depopulate. Online Etymology Dictionary. Retrieved $(datetime), from https://www.etymonline.com/word/depopulate