deplore v.

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-.

1610s, "that may or must be deplored, lamentable, grievous, miserable;" from 1640s as "pitiable, wretched, contemptible," 1610s, from -able + deplore (v.) "lament, bewail, give up as hopeless," from French déplorer (13c.), from Latin deplorare "bewail, lament, give up for lost," from de- "entirely" (see de-) + plorare "weep, cry out," which is of unknown origin.

Perhaps from or inspired by French déplorable or directly from Late Latin deplorabilis. "It is sometimes, in a more lax and jocular sense, used for contemptible; despicable: as deplorable nonsense; deplorable stupidity" [Johnson, 1755]. Related: Deplorably; deplorableness; deplorability.

As a noun it is attested from 1830 as "deplorable ills." Deplorables was used politically in reference to the ministry of Charles X of France in the 1820s (le ministère déplorable). Rare in 19c.-20c.; in U.S. it got a boost 2016 when used by presidential candidate Hillary Clinton in reference to supporters of her rival, Donald Trump, some of whom embraced it as a despite-word.

1580s, "to investigate, examine," a back-formation from exploration, or else from French explorer (16c.), from Latin explorare "investigate, search out, examine, explore," said to be originally a hunters' term meaning "set up a loud cry," from ex "out" (see ex-) + plorare "to weep, cry." Compare deplore. De Vaan notes modern sources that consider "the ancient explanation, ... that the verb explorare originally meant 'to scout the hunting area for game by means of shouting'" to be "not unlikely." Second element also is explained as "to make to flow," from pluere "to flow." Meaning "to go to a country or place in quest of discoveries" is first attested 1610s. Related: Explored; exploring.