膨らむ・脹らむ|ふくらむfukuramu[0]heiban (flat)

1. godan verb, intransitive verbto expand; to swell (out); to get big; to become inflated
   一陣いちじんの風かぜをうけて帆ほがふくらんだ。↗

   A gust of wind swelled the sails.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• Synonym膨れるふくれるNeutralSwelling or puffing up, and also sulking or pouting, as in 「ほっぺたが膨れる」; 「膨らむ」 is more for balloons, expectations and the like.
• Synonym腫れるはれるNeutralRed swelling from inflammation or a bump, as in 「目が腫れる」; tied to injury and illness, which 「膨らむ」 is not.
• Synonym増すますNeutralIncreasing or intensifying, as in 「人気が増す」; leans toward degree and quantity, fine in both speech and writing.
• Related膨張ぼうちょうWrittenWritten, formal word for expansion of volume or scale, as in 「都市の膨張」; used mostly in physics and economics.
• Related拡大かくだいNeutralEnlargement of scale or scope, as in 「事業を拡大する」 or 「被害が拡大する」; does not describe a bulging shape.
• Related広がるひろがるNeutralSpreading outward over an area, as in 「噂が広がる」; leans toward flat spreading out, while 「膨らむ」 leans toward bulging bigger.
• Related伸びるのびるNeutralGrowing longer or increasing, as in 「背が伸びる」 or 「売り上げが伸びる」; focuses on gains in length.
• Related増えるふえるNeutralNumbers increasing, as in 「人口が増える」; purely about quantity, with no sense of a bulging shape.
• Related拡張かくちょうNeutralExpansion or extension, as in 「道路を拡張する」; leans toward deliberate widening of facilities or functions.
• Related張るはるNeutralStretching tight, spreading, or forming ice, as in 「氷が張る」; can also mean filling out and bulging — many uses.
• Related伸長しんちょうWrittenWritten word for growth of influence or results, as in 「輸出の伸長」; leans toward abstract increase.
• Related張り出すはりだすNeutralProjecting outward or posting a notice, as in 「張り出した窓」; leans toward a part sticking out.
• Related増加ぞうかNeutralSino-Japanese word for a rise in numbers, as in 「人口増加」; leans toward statistics, with no bulging nuance.
• Related膨れ上がるふくれあがるNeutralSwelling up hugely or ballooning in number, as in 「赤字が膨れ上がる」; a stronger degree than 「膨らむ」.
• Related伸展しんてんWrittenWritten word for extending one's influence or business; rarely used, and abstract in flavor.
• RelatedむくむNeutralBodily puffiness, as in 「足がむくむ」; specifically water retention, never for balloons or plans.
• Related膨潤ぼうじゅんWrittenWritten term for a material swelling as it absorbs liquid; a chemistry and biology term.
• Related増さるまさるWrittenWritten word for increasing in amount or degree; rare today — say 「増す」 in daily life.
• Antonym縮むちぢむNeutralAntonym: shrinking or getting smaller, the opposite of 「膨らむ」 bulging bigger.
• Antonym凹むへこむNeutralAntonym: a surface caving in, opposite to 「膨らむ」; colloquially also feeling deflated.
• Antonym窪むくぼむNeutralAntonym: sinking in or hollowing, opposite to 「膨らむ」 bulging outward; leans toward terrain or surfaces.

Use 「膨らむ」 for something swelling out bigger from internal force — balloons, expectations, budgets. For puffing up or sulking pick 「膨れる」, for ballooning or sharp increases 「膨れ上がる」, for red swelling from injury 「腫れる」, and for numbers simply going up 「増える」. The opposites are 「縮む」 and 「へこむ」.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

1. 内部ないぶからの力ちからで球形きゅうけいに大おおきくなる。
2. 規模きぼ、数量すうりょうなどが大おおきくなる。
3. 期待きたいや疑惑ぎわくなどの観念かんねんがおおきくなる。ひろがる。