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verb de·cay \di-ˈkā\

Simple Definition of decay

  • : to be slowly destroyed by natural processes : to be slowly broken down by the natural processes that destroy a dead plant or body

  • : to slowly lose strength, health, etc.

  • of a building, area, etc. : to go slowly from a bad condition to a worse condition : to slowly enter a state of ruin

Source: Merriam-Webster's Learner's Dictionary

Full Definition of decay

  1. intransitive verb
  2. 1 :  to decline from a sound or prosperous condition

  3. 2 :  to decrease usually gradually in size, quantity, activity, or force

  4. 3 :  to fall into ruin

  5. 4 :  to decline in health, strength, or vigor

  6. 5 :  to undergo decomposition <decaying fruit>

  7. transitive verb
  8. 1 obsolete :  to cause to decay :  impair <infirmity that decays the wise — Shakespeare>

  9. 2 :  to destroy by decomposition

decayer noun

Examples of decay in a sentence

  1. the smell of decaying rubbish

  2. dead plants and leaves decayed by bacteria

  3. She believes that the moral fiber of our society is decaying.

  4. our decaying public school system

  5. The city's neighborhoods are decaying.

Origin of decay

Middle English, from Anglo-French decaïr, from Late Latin decadere to fall, sink, from Latin de- + cadere to fall — more at chance

First Known Use: 15th century

Synonym Discussion of decay

decay, decompose, rot, putrefy, spoil mean to undergo destructive dissolution. decay implies a slow change from a state of soundness or perfection <a decaying mansion>. decompose stresses a breaking down by chemical change and when applied to organic matter a corruption <the strong odor of decomposing vegetation>. rot is a close synonym of decompose and often connotes foulness <fruit was left to rot in warehouses>. putrefy implies the rotting of animal matter and offensiveness to sight and smell <corpses putrefying on the battlefield>. spoil applies chiefly to the decomposition of foods <keep the ham from spoiling>.

Rhymes with decay

abbé, affray, agley, airplay, airway, aisleway, all-day, allay, allée, Angers, Anhui, archway, array, ashtray, assay, astray, Augier, away, aweigh, backstay, ballet, base pay, bat ray, beignet, belay, beltway, benday, beret, betray, bewray, bidet, bikeway, birthday, Biscay, Bizet, blasé, bobstay, Bombay, Bossuet, bouchée, bouclé, boule, bouquet, Bourget, bourrée, breezeway, Bouvet, Broadway, buffet, byplay, byway, cachet, café, cahier, Cambay, Cathay, causeway, chaîné, chalet, chambray, chassé, child's play, ciré, cliché, congé, convey, co-pay, Corday, corvée, coudé, coupé, crawlway, crochet, croquet, crossway, cube, curé, cy pres, DA, daresay, D-day, death ray, deejay, defray, delay, dengue, dismay, display, distrait, DJ, donnée, doomsday, doorway, dossier, downplay, dragée, driveway, duvet, Earl Grey, embay, épée, essay, estray, Ewe, fair play, fairway, Feuillet, field day, filé, filet, fillet, fireclay, fishway, flambé, flight pay, floodway, flyway, folkway, footway, foray, force play, forebay, foreplay, forestay, formée, forte, fouetté, foul play, Fouquet, four-way, fourchée, foyer, franglais, frappé, freeway, Friday, frieze, fumet, gainsay, Galway, gamay, gangway, gateway, gelée, give way, glacé, godet, gourmet, Green Bay, greenway, guideway, gunplay, hair spray, halfway, hallway, Hannay, harm's way, hatchway, headway, hearsay, Hebei, Hefei, heyday, highway, hold sway, homestay, hooray, horseplay, Hubei, in play, in re, inlay, inveigh, Islay, issei, jackstay, James Bay, jennet, jeté, Jetway, Jolliet, keyway, Kobe, koine, kouprey, lamé, laneway, lay day, leeway, lifeway, Lomé, Lord's day, lwei, lycée, M-day, maguey, mainstay, make hay, Malay, malgré, man-day, Mande, Manet, manqué, margay, massé, match play, maté, May Day, Medway, melee, meze, midday, midway, Midway, Millay, Millet, mislay, misplay, moiré, Monday, Monet, Mornay, name day, Niamey, nisei, noonday, Norway, nosegay, obey, OK, olé, ombré, one-way, osprey, Otway, outlay, outré, outstay, outweigh, oyez, PA, parfait, parkway, parlay, parquet, partway, passé, pâté, pathway, pavé, payday, pearl gray, per se, pince-nez, pipe clay, piqué, piquet, pith ray, PK, plié, plissé, pommée, Pompeii, portray, prepay, projet, pulque, puree, purvey, quale, Quesnay, raceway, Rahway, railway, rappee, red bay, relay, repay, replay, risqué, roadway, Roget, role-play, ropeway, rosé, rosebay, Roubaix, roué, routeway, runway, sachet, saint's day, Salé, sansei, sashay, sauté, screenplay, scrub jay, seaway, Shark Bay, shar-pei, shipway, short-day, sick bay, sick day, sick pay, sideway, skyway, slideway, slipway, sluiceway, soigné, soiree, someday, someway, soothsay, soufflé, speedway, spillway, squeeze play, stairway, sternway, stingray, straightway, strathspey, stroke play, subway, Sunday, survey, sweet bay, swordplay, tea tray, tempeh, thoughtway, thruway, Thursday, tideway, today, Tokay, tollway, Torbay, touché, toupee, trackway, tramway, Tuesday, Twelfth Day, two-way, unlay, unsay, valet, V-day, veejay, vide, visé, Vouvray, walkway, waylay, Wednesday, weekday, white way, windway, wood ray, wordplay, workday



noun de·cay

Simple Definition of decay

  • : the process or result of being slowly destroyed by natural processes

  • : the slow loss of strength, health, etc.

  • of a building, area, etc. : the process or result of going slowly from a bad condition to a worse condition

Source: Merriam-Webster's Learner's Dictionary

Full Definition of decay

  1. 1 :  gradual decline in strength, soundness, or prosperity or in degree of excellence or perfection

  2. 2 :  a wasting or wearing away :  ruin

  3. 3 obsolete :  destruction, death

  4. 4 a :  rot; specifically :  aerobic decomposition of proteins chiefly by bacteria b :  the product of decay

  5. 5 :  a decline in health or vigor

  6. 6 :  decrease in quantity, activity, or force: as a :  spontaneous decrease in the number of radioactive atoms in radioactive material b :  spontaneous disintegration (as of an atom or a particle)

Examples of decay in a sentence

  1. the decay of dead plants and leaves

  2. She writes about the moral decay of our society.

  3. the patient's physical and mental decay

  4. The city's neighborhoods are in slow decay.

15th Century

First Known Use of decay

15th century

DECAY Defined for Kids



verb de·cay \di-ˈkā\

Definition of decay for Students


  1. 1 :  to break down or cause to break down slowly by natural processes <Fruit decayed on the ground.> <Sugar decays teeth.>

  2. 2 :  to slowly worsen in condition <The old theater decayed.>



noun de·cay

Definition of decay for Students

  1. 1 :  the process or result of slowly breaking down by natural processes <The schoolhouse being deserted soon fell to decay … — Washington Irving, “Sleepy Hollow”>

  2. 2 :  a gradual worsening in condition <a decay in manners>

  3. 3 :  a natural change of a radioactive element into another form of the same element or into a different element

Seen and Heard

What made you want to look up decay? Please tell us where you read or heard it (including the quote, if possible).


immature or lacking adult sophistication

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