衰え|おとろえotoroe[3]nakadaka (mid-high)

1. nounweakening; emaciation; decline
   自分じぶんの衰おとろえを感かんじた事ことがありますか。↗

   Do you ever feel like you're running down?

• Synonym衰退すいたいWrittenWritten/formal word for the decline of nations, industries and the like; 「衰え」 is the everyday term, mostly for failing strength or ability.
• Synonym減退げんたいWrittenThe fading of functions such as appetite or sexual desire — a matter of a function weakening, not overall decline. Written/formal.
• Synonym退潮たいちょうWrittenLiterally the ebbing tide; figuratively the waning of momentum, as in 「人気の退潮」. Written/formal.
• Synonym弱まりよわまりNeutralA weakening in force or intensity — the degree simply grows smaller. Narrower in use than 「衰え」 and not usually said of bodily functions. Neutral.
• Synonym減衰げんすいWrittenWritten/formal word for gradual attenuation, mainly of signals and vibrations; 「筋力の減衰」 is also possible.
• Synonym退勢たいせいWrittenRare written word for a declining trend, used of situations and of forces, never of physical strength.
• Synonym萎靡いびWrittenRare written word for listless, dispirited decline; used of morale or of industries.
• Synonym衰勢すいせいWrittenRare written word for declining momentum, used of a nation's or a family's fortunes, not of personal physical strength.
• Synonym衰微すいびWrittenWritten/formal word for the gradual fading of a nation or family that was once prosperous.
• Synonym凋残ちょうざんWrittenRare literary word for withering and decay, used of scenery and of a family business.
• Synonym凋落ちょうらくWrittenFlowers withering and falling; by extension the fall of a family's fortunes or of a power. Written/formal.
• Synonym弱化じゃっかWrittenBeing weakened, typically said of organizations and forces, as in 「弱化した」. Written/formal.
• Related退廃たいはいWrittenDecadence and corruption: the rotting of morals, spirit and public mores. Where 「衰え」 is a weakening, 「退廃」 stresses corruption. Written/formal.
• Related低下ていかNeutralA drop in figures or in ability, as in 「視力の低下」; a neutral, very widely used word.
• Related下落げらくNeutralFalling prices or market quotations — an economic term; not used of physical strength or ability. Neutral.
• Related後退こうたいNeutralA retreat or falling back; also economic recession, as in 「景気後退」. Neutral.
• Related下り坂くだりざかNeutralLiterally a downhill slope; figuratively on the way down. Colloquial and vivid.
• Related下向きしたむきNeutralPointing down; also a downward market trend — leans economic. Neutral.
• Related衰滅すいめつWrittenDecline carried through to ruin and extinction — a far deeper stage than 「衰え」. Written/formal.
• Related落潮らくちょうWrittenThe falling tide; figuratively the waning of a power's fortunes. A rare written word, not used of the body.
• Antonym盛りさかりNeutralThe peak or prime of something, as in 「花の盛り」 — the opposite pole of 「衰え」. Neutral.
• Antonym勢いいきおいNeutralVigor, force, momentum — what 「衰え」 is the loss of; its antonym. Neutral.

Use 「衰え」 for everyday weakening of body or ability, as in 「体力の衰え」. For nations and industries say 「衰退」; for falling figures or eyesight, 「低下」; for appetite or libido, 「減退」. 「下落」 and 「下向き」 are for prices and markets, 「後退」 for retreat and recession, 「下り坂」 is a colloquial, vivid image of decline. Rarer written words — 「退廃」 moral decay, 「退潮」/「落潮」 ebbing fortunes, 「衰微」/「衰勢」/「退勢」 fading nations and families, 「凋残」/「凋落」 literary withering, 「衰滅」 ruin, 「弱化」/「減衰」 being weakened — not everyday swaps. Opposites: 「盛り」, 「勢い」.

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

1. 衰おとろえること。衰微すいび。衰退すいたい。衰弱すいじゃく。