Meaning
肥 (JLPT N1) covers two closely linked ideas: fat or plump for living creatures, and fertile, rich, or fertilizer for the land. A well-fed animal and nutrient-dense soil feel unrelated — but both describe the same process: something has been accumulating nourishment over time.
肥 is built from two components. On the left is 月 — not the moon here, but a compressed form of 肉 (meat, flesh). On the right, 巴 depicts a coiling shape: a snake curling inward, or the spiral of packed intestines. Together they picture fat layering around the body's core. That same image of accumulation extended to the land — earth enriched with organic matter, growing rich the way a well-fed body does.
肥 has 8 strokes and is a Grade 5 Jōyō kanji taught in primary school. It shows up at JLPT N1 because its vocabulary spans agriculture, medicine, and old provincial geography. Master it and you gain access to a tight cluster of terms — soil science, nutrition disorders, and at least one pointed corruption idiom.
Readings
On'yomi (音読み) — Chinese-derived readings
ヒ (hi) is the sole on'yomi and the reading you'll encounter most. It drives virtually all compound words and is standard in medical, agricultural, and formal writing — newspapers, academic texts, official documents. For N1, focus on recognizing ヒ in compound context rather than drilling it in isolation.
- 肥料 (hiryō) — fertilizer; added to soil to sustain plant growth and crop yield
- 肥満 (himan) — obesity; the medical condition of excess body fat accumulation
- 肥大 (hidai) — hypertrophy; abnormal enlargement of an organ or tissue
- 肥沃 (hiyoku) — fertile; describes land dense with nutrients and well-suited for crops
- 施肥 (sehi) — fertilizer application; adding fertilizer to farmland during the growing season
- 堆肥 (taihi) — compost; decomposed organic matter used as a natural soil amendment
Kun'yomi (訓読み) — Native Japanese readings
The kun'yomi forms are こ.える (ko.eru) and こ.やす (ko.yasu), used as standalone verbs with okurigana. The noun こえ (koe) means manure. These appear in everyday farm talk, proverbs, and idioms. One nuance worth knowing: こえる has a figurative use the on'yomi forms lack — it describes a discerning eye or refined palate built through long experience.
- 肥える (koeru) — to grow fat (animals or people); to become fertile (land); to develop a keen, discerning sense of taste or aesthetic judgment
- 肥やす (koyasu) — to fatten livestock; to fertilize soil; figuratively, to line one's own pockets through dishonest means
- 肥え (koe) — manure; organic fertilizer from animal waste or decomposed plant matter
Common Words & Compounds
肥 appears across a wide range of registers — from the rice paddy to the clinic to the courtroom.
Agricultural terms:
- 肥料 (hiryō) — fertilizer; the core input for keeping soil productive season after season
- 堆肥 (taihi) — compost; kitchen scraps and plant matter broken down into natural fertilizer
- 肥沃 (hiyoku) — fertile; soil dense with nutrients, ideal for growing crops
- 施肥 (sehi) — fertilizer application; working fertilizer into farmland before or during the growing season
- 肥育 (hiiku) — livestock fattening; raising animals specifically to build body weight for meat production
- 有機肥料 (yūki hiryō) — organic fertilizer; made from natural sources such as bone meal, seaweed, or compost
Medical and body-related terms:
- 肥満 (himan) — obesity; linked to elevated risk of diabetes, heart disease, and other chronic conditions
- 肥大 (hidai) — hypertrophy; abnormal enlargement of an organ, as in cardiac hypertrophy
- 肥大化 (hidaika) — becoming bloated or oversized; used for organs but also for bureaucracies that have grown unwieldy
Idiomatic expressions:
- 私腹を肥やす (shifuku wo koyasu) — to line one's own pockets; to grow personally wealthy through corrupt or illicit means
- 目が肥える (me ga koeru) — to develop a discerning eye; to build refined aesthetic judgment through years of exposure
Historical geographic names:
- 肥前 (Hizen) — former province covering modern Saga and Nagasaki prefectures in Kyushu
- 肥後 (Higo) — former province covering modern Kumamoto prefecture in Kyushu
Example Sentences
この地域の土はとても肥えている。
Kono chiiki no tsuchi wa totemo koete iru.
The soil in this region is extremely fertile.
農家は毎年春に肥料を畑にまく。
Nōka wa maitoshi haru ni hiryō wo hatake ni maku.
— Farmers spread fertilizer on their fields every spring.
肥満は生活習慣病のリスクを高める。
Himan wa seikatsu shūkanbyō no risuku wo takameru.
— Obesity raises the risk of lifestyle-related diseases.
堆肥を使えば土が自然に肥える。
Taihi wo tsukaeba tsuchi ga shizen ni koeru.
— Using compost naturally enriches the soil.
芸術に触れることで、目が肥えてくる。
Geijutsu ni fureru koto de, me ga koete kuru.
Spending time with art gradually sharpens your eye.
その政治家は私腹を肥やして逮捕された。
Sono seijika wa shifuku wo koyashite taiho sareta.
That politician was arrested for lining their own pockets.
医師は患者の心臓肥大を発見した。
Ishi wa kanja no shinzō hidai wo hakken shita.
— The doctor found cardiac hypertrophy in the patient.
肥沃な大地では様々な作物が育つ。
Hiyoku na daichi de wa samazama na sakumotsu ga sodatsu.
— All kinds of crops thrive on fertile land.
放牧された牛はよく肥えていた。
Hōboku sareta ushi wa yoku koete ita.
— The pasture-raised cattle had grown plump and healthy.
有機肥料は環境に優しく、土を長期的に肥やす。
Yūki hiryō wa kankyō ni yasashiku, tsuchi wo chōkiteki ni koyasu.
Organic fertilizers are gentler on the environment and enrich the soil over time.
Memory Tip
肥 tells the same story in two parts. Left side: 月, standing in for 肉 (flesh). Right side: 巴, a coiling spiral — picture a snake curled inward, or fat wrapping layer by layer around the body's core. That image of gradual accumulation is the heart of the character.
The idiom 私腹を肥やす gives you a second hook: greed coiling like a snake, quietly gathering whatever it can reach. A plump well-fed animal, dark nutrient-rich soil, a corrupt official growing quietly wealthy — 肥 tells the same story each time. Keep that coiling image in mind and the kanji will stick.