减肥(jiǎn féi) - to lose weight, to slim in Mandarin

减肥 (jiǎnféi) means "to lose weight" or "to slim", literally "reduce fat": 减 (jiǎn) is "to reduce, subtract" and 肥 (féi) is "fat". It is the everyday word for a deliberate effort to lose weight, whether through diet, exercise, or both.

减肥 (jiǎnféi) works as a stand-alone verb without an object: 我在减肥 (wǒ zài jiǎnféi), "I'm on a diet / I'm trying to lose weight", is complete on its own, unlike English "lose weight" which usually wants something after it.

Its natural partners are 胖 (pàng), "fat", the state someone is trying to move away from, and 瘦 (shòu), "thin", the state they are aiming for. 运动 (yùndòng), "to exercise", is the method most often paired with it in advice: 运动减肥 (yùndòng jiǎnféi), "to lose weight through exercise".