agitate:  Agitate is one of a host of English words descended ultimately from Latin agere (see AGENT). Among the many meanings of agere was ‘drive, move’, and a verb derived from it denoting repeated action, agitāre, hence meant ‘move to and fro’. This physical sense of shaking was present from the start in English agitate, but so was the more metaphorical ‘perturb’.
The notion of political agitation does not emerge until the early 19th century, when the Marquis of Anglesey is quoted as saying to an Irish deputation: ‘If you really expect success, agitate, agitate, agitate!’ In this meaning, a derivative of Latin agitāre has entered English via Russian in agitprop ‘political propaganda’ , in which agit is short for agitatsiya ‘agitation’. => act, agent
1580s, "to disturb," from Latin agitatus, past participle of agitare "to put in constant motion, drive onward, impel," frequentative of agere "to move, drive" (see agitation). Literal sense of "move to and fro, shake" is from 1590s. Related: Agitated; agitating.
1. The women who worked in these mills had begun to agitate for better conditions.
2. All you need to do is gently agitate the water with a finger or paintbrush.