The social level of a word — Colloquial (knock, rip, slam), Neutral (criticize, fault), Academic (censure, impugn), Elevated/literary (excoriate, inveigh against). The examination's texts sit in a narrow formal band, so the correct option is almost always Neutral or Academic; an option that breaks the band is wrong even when its denotation fits. The fanciest word is wrong at least as often as it is right.