Loutishly tells you how someone did something: in a rude, rough, badly brought-up way. He laughed loutishly means the laugh itself felt coarse, as if he did not care who he hurt. You add -ly when you want to paint the action, not the person. It is not a common word in speech; people are more likely to say rudely or like a lout. When you do meet loutishly, it is often in writing that wants a sharp, old-fashioned sting. Though actually, it still points at the same ugly manners as lout — shoving, shouting, making a mess of other people’s space — not at simple clumsiness. A child who spills a drink is not acting loutishly unless they are also being coarse on purpose. Use it sparingly. It is a heavy little hammer of a word.

粗魯地、沒教養地（副詞，修飾動作，不是指那個人本身）