late 15c., "living creature killed and offered as a sacrifice to a deity or supernatural power, or in the performance of a religious rite;" from Latin victima "sacrificial animal; person or animal killed as a sacrifice," a word of uncertain origin. Perhaps related to vicis "turn, occasion" (as in vicarious), if the notion is an "exchange" with the gods. Perhaps distantly connected to Old English wig "idol," Gothic weihs "holy," German weihen "consecrate" (compare Weihnachten "Christmas") on notion of "a consecrated animal."
Sense of "person who is hurt, tortured, or killed by another" is recorded from 1650s; meaning "person oppressed by some power or situation, person ruined or greatly injured or made to suffer in the pursuit of an object, or for the gratification of a passion or infatuation, or from disease or disaster" is from 1718. Weaker sense of "person taken advantage of, one who is cheated or duped" is recorded from 1781.