Victimization is the act of treating someone badly and unfairly, on purpose, because of who they are or what they believe — their race, their religion, their politics, their union membership, or simply because you have decided you do not like them. It is the noun that names the whole behaviour: "the victimization of migrant workers" means migrant workers being treated this way.

Two places you will really meet it. First, at work and in law. If a worker complains about their boss and is then given the worst shifts, passed over, or pushed out, that is victimization — being punished for speaking up. In British employment law this is a technical term with a precise meaning, and people bring cases about it. Second, in the study of crime. There, victimization simply means being the target of a crime, with no unfairness needed: researchers count "rates of victimization" the way they count rates of anything, and a "victimization survey" asks ordinary people whether crime has happened to them.

So the word wears two hats — unfair treatment in one setting, being a crime target in the other — and the setting tells you which.

It is formal and rather heavy, at home in reports, laws, and news. In everyday talk people say "they picked on him" or "they had it in for her" instead. It is uncountable, so no plural.

Spelling: British writing often prefers victimisation with an s, American writing uses the z. Both are correct; just be consistent.