deprogram (v.)

1889, "write program notes" (a sense now obsolete); 1896 as "arrange according to program," from program (n.).

Of computers, "cause to be automatically regulated in a prescribed way" from 1945; this was extended to animals by 1963 in the figurative sense of "to train to behave in a predetermined way;" of humans by 1966. Related: Programmed; programming.

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-.