fat

Compared meaning: weighing more than is healthy or normal (adjective).

比较义项：体重过重、肥胖（形容词）。

• fat 本词

  Blunt and informal; often sounds negative or rude when applied to people, though harmless for animals or in casual speech.

  直接且口语化；用于人时常显得负面或不礼貌，但用于动物或随意口语时则无冒犯之意。

  Stop eating junk food or you'll get fat, his mom warned him.

  他妈妈警告他，再吃垃圾食品就会变胖。

• overweight

  Neutral and clinical, often used by doctors or in health contexts to describe a measurable, moderate excess of body weight.

  中性、客观，常用于医生或健康语境中，描述可测量的、中等程度的体重超标。

  The doctor said the dog was slightly overweight and needed more exercise.

  医生说这只狗有点超重，需要多运动。

• plump

  Softly positive or affectionate, suggesting a pleasantly rounded, healthy-looking body rather than a health problem.

  带有轻微的褒义或亲切感，形容体态丰满、看起来健康可爱，而非有健康问题。

  The baby had plump little cheeks that everyone loved to pinch.

  这个婴儿有丰满的小脸蛋，大家都喜欢捏一捏。

• obese

  A formal, medical term for a severe, health-threatening degree of excess weight, typically defined by BMI.

  正式的医学用语，指严重到危害健康的肥胖程度，通常以体质指数（BMI）界定。

  The vet warned that the cat was becoming dangerously obese and at risk of diabetes.

  兽医警告说，这只猫正变得严重肥胖，有患糖尿病的风险。

These words all describe someone heavier than average, but with different tones. Fat is blunt, even rude. Overweight is neutral and clinical, common with doctors. Plump sounds gentle and positive, suggesting a healthy roundness. Obese is a formal medical term for health-threatening excess weight.

这些词都表示体重超出正常范围，但语气强弱和感情色彩不同：fat 直接甚至带贬义，overweight 中性客观（常见于医学语境），plump 略带亲切积极的意味，obese 是严重且带医学色彩的肥胖，程度最重。

Compared meaning: containing a lot of fat or oil (adjective).

比较义项：含有大量油脂或脂肪（形容词）。

• fat 本词

  Describes meat with a lot of visible fat, as opposed to lean; a blunt, everyday word mainly used before 'meat' or 'bacon', rarely used for other greasy foods.

  多用于形容带有大量肥肉的肉类（与“瘦”相对），语气直白、口语化，通常只用在“肉”“培根”等词前面，很少用来形容其他油腻的食物。

  She trimmed the fat meat off before frying the pork chops.

  她在煎猪排之前把肥肉切掉了。

• greasy

  Suggests a slick, unpleasant coating of oil or fat, often with a negative tone; common for fried food and also greasy skin or hair.

  强调表面沾满油脂、让人觉得不舒服，语气偏负面，常用来形容炸食品，也可以形容出油的皮肤或头发。

  The greasy pizza left oil stains on the napkin.

  油腻的比萨在餐巾纸上留下了油渍。

• fatty

  A neutral, clinical term for high fat content, typical in nutrition and medical contexts, as in 'fatty food', 'fatty liver' or 'fatty acids'.

  语气中性、偏专业，常见于营养学或医学语境，如“高脂肪食物”“脂肪肝”“脂肪酸”等表达。

  Doctors advise cutting back on fatty foods to protect your heart.

  医生建议少吃高脂肪食物以保护心脏。

• oily

  Describes something naturally producing or coated with oil, such as skin or hair, without the negative tone of 'greasy'; also used in 'oily fish' like salmon.

  形容本身出油或表面沾油的东西，如皮肤、头发，语气不像 greasy 那样负面；也常用在“oily fish”（油性鱼）这样的说法中，比如三文鱼。

  Her oily skin starts to shine again by midafternoon.

  她的皮肤很爱出油，到下午就又开始发亮了。

Fat, greasy, fatty, oily all mean having much fat or oil. Fat: meat with visible fat, blunt. Greasy: an unpleasant oily coating, often negative. Fatty: neutral, scientific (fatty food). Oily: naturally coated in oil, like skin or hair.

这四个词在“含油脂多”这个意思上很接近，但语气和使用场合不同：fat 多用于形容带肥肉的肉类，语气直白甚至有点粗略；greasy 强调表面油腻、让人不舒服，语气偏负面；fatty 是营养学、医学语境里中性的专业说法；oily 指本身出油或沾有油，语气比较中性。这里不比较 fat 表示“（人、动物）肥胖”的义项，也不比较 oily 表示“油滑、讨好”的引申义。