Critique is an alteration of an archaic word that referred generally to criticism. Critique itself dates to the early 18th century and originally referred to a piece of writing that criticized a literary or artistic work. The words criticism, critique, and review overlap in meaning. Criticism usually means "the act of criticizing" or a "remark or comment that expresses disapproval," but it can also refer to the activity of making judgments about the qualities of books, movies, etc. (as in "literary criticism"). Critique is a somewhat formal word that typically refers to a careful judgment in which someone gives an opinion about something. Review can refer to an essay analyzing a literary or artistic work, but can also sometimes imply a more casual or personal opinion.
Foucault gives us an indication of what he means by virtue in the introduction to The Use of Pleasure: The History of Sexuality, Volume Two.  At this juncture he makes clear that he seeks to move beyond a notion of ethical philosophy that issues a set of prescriptions. Just as critique intersects with philosophy without quite coinciding with it, so Foucault in that introduction seeks to make of his own thought an example of a non-prescriptive form of moral inquiry. In the same way, he will later ask about forms of moral experience that are not rigidly defined by a juridical law, a rule or command to which the self is said mechanically or uniformly to submit. The essay that he writes, he tells us, is itself the example of such a practice, “to explore what might be changed, in its own thought, through the practice of a knowledge that is foreign to it.” (9) Moral experience has to do with a self-transformation prompted by a form of knowledge that is foreign to one’s own. And this form of moral experience will be different from the submission to a command. Indeed, to the extent that Foucault interrogates moral experience here or elsewhere, he understands himself to be making an inquiry into moral experiences that are not primarily or fundamentally structured by prohibition or interdiction.