agitprop n.

1560s, "debate, discussion" (on the notion of "a mental tossing to and fro"), from French agitation, from Latin agitationem (nominative agitatio) "motion, agitation," noun of action from past-participle stem of agitare "move to and fro," frequentative of agere "to set in motion, drive forward; keep in movement" (from PIE root *ag- "to drive, draw out or forth, move").

The physical sense of "state of being shaken or moving violently" is from 1580s; the meaning "state of being mentally agitated" is from 1722; that of "arousing and sustaining public attention" to some political or social cause is from 1828. Old English glossed Latin agitatio with unstilnis.

1718, "committee of cardinals in charge of foreign missions of the Catholic Church," short for Congregatio de Propaganda Fide "congregation for propagating the faith," a committee of cardinals established 1622 by Gregory XV to supervise foreign missions. The word is properly the ablative fem. gerundive of Latin propagare "set forward, extend, spread, increase" (see propagation).

Hence, "any movement or organization to propagate some practice or ideology" (1790). The modern political sense ("dissemination of information intended to promote a political point of view") dates from World War I, not originally pejorative and implying bias or deliberate misleading. Meaning "material or information propagated to advance a cause, etc." is from 1929. Related: Propagandic.