a cupboard or a small room with a door, used for storing things, especially clothes

a bedroom/linen/storage closet 卧室壁橱／家庭日用织品柜橱／储藏室

to put yourself in a place, especially a closed space, and stay there

Two weeks before my exams I closeted myself (away) in my room with my books and I didn't speak to anyone. 考试前两星期，我把自己关在房里读书，不跟任何人说话。

The president has been closeted with (= having a private meeting with) his advisers for several hours. 总统与顾问们已经密谈了好几个小时了。

used to refer to a belief, activity, or feeling that is kept secret from the public, usually because you are frightened of the results of it becoming known

a closet alcoholic/smoker 不愿承认的酗酒者/吸烟者

Dole portrayed the president in campaign speeches as a "closet liberal". 多尔在竞选演讲中将总统描绘为“藏而不露的自由主义者”。