減衰|げんすいgensui[0]heiban (flat)

1. noun, suru verb, intransitive verbattenuation; damping; decay

• Synonym減退げんたいWrittenWritten/formal prose. Covers waning of physical strength or appetite, as in 「食欲減退」; 「減衰」 is about signals or energy gradually fading.
• Synonym低下ていかNeutralNeutral. A drop or lowering, as in 「能力の低下」; broad in scope and focused on degree or level falling.
• Synonym衰えおとろえNeutralNeutral noun for weakening, as in 「体力の衰え」; leans toward bodily functions.
• Synonym弱るよわるCasualColloquial verb for growing weak, also for being at a loss, as in 「体が弱る」; leans toward the body.
• Synonym減少げんしょうNeutralNeutral. A decrease in quantity, as in 「人口減少」 or 「エネルギーの減少」; focuses on numbers falling.
• Synonym衰えるおとろえるNeutralNeutral verb for weakening or declining, common in daily use and leaning toward bodies and powers; 「減衰」 is for signals and energy.
• Synonym衰退すいたいNeutralNeutral. The decline of industries or culture, as in 「産業の衰退」; leans toward society at large.
• Synonym衰微すいびWrittenWritten/formal prose. The decline of nations or industries, with a historical flavor; not used for physical signals.
• Synonym衰耗すいもうWrittenWritten/formal prose for weakening and wearing out, but rare; 「衰弱」 is the usual word.
• Synonym低まるひくまるWrittenWritten/formal prose for height or degree becoming lower, but rare; 「低くなる」 is the usual phrasing.
• Synonym減ずるげんずるWrittenWritten/formal prose for decreasing or lessening; works as a transitive verb too, and is close to 「減衰」.
• Related下落げらくNeutralNeutral. A fall in price or value, as in 「株価の下落」; leans toward markets.
• Related後退こうたいNeutralNeutral. Moving backward, also economic recession as in 「景気後退」; stresses retreat or reversal.
• Related下り坂くだりざかCasualColloquial. A downhill slope, used figuratively for going into decline, as in 「人気が下り坂」.
• Related退潮たいちょうNeutralNeutral. The ebbing of a force's power, as in 「退潮傾向」; leans toward politics and trends.
• Related没落ぼつらくWrittenWritten/formal prose for the fall of a family or nation, as in 「没落貴族」; carries a tragic tone.
• Related凋落ちょうらくWrittenWritten/formal prose. Withering decline, as in 「凋落ぶり」; carries a mournful tone and is said mostly of people or powers.
• Related衰滅すいめつWrittenWritten/formal prose for declining until vanishing; rare, and stronger in degree than 「減衰」.
• Related萎靡いびWrittenWritten/formal prose for listlessness and loss of drive, said of morale or social climate; rare.
• Related凋残ちょうざんWrittenWritten/formal prose for flowers and plants withering away; rare and literary in flavor.
• Antonym増幅ぞうふくWrittenAntonym. Written/formal prose for amplifying a signal or enlarging something; the opposite of 「減衰」's fading.
• Antonym増大ぞうだいNeutralAntonym. Growth or enlargement, as in 「需要の増大」; the opposite of 「減衰」's weakening.

Use 「減衰」 for signals, vibrations, or energy gradually fading, as in 「信号が減衰する」. For waning appetite or desire pick 「減退」, for the decline of industries 「衰退」, for falling numbers 「減少」, and for amplification 「増幅」. Other shades: 「低下」 and 「下落」 for drops in level or value, 「衰える」 and 「衰え」 for weakening of body or power, 「没落」 and 「衰微」 for the fall of families or nations, 「下り坂」 for going downhill.

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

1. 徐々じょじょに減へっていくこと。