decayed

IPA/dɪˈkeɪ/
KK[dəkˈed]IPA/dɪˈkeɪ/

decayed — verb

  • decayedpresent simple I / you / we / they
  • decayeds3rd person singular
  • decayeding-ing form
  • decayededpast simple

1. to slowly fall apart, lose strength, or get into worse condition over time; also

1.verbtransitive / intransitiveB2
Definition

to slowly fall apart, lose strength, or get into worse condition over time; also, to make something do this

Example

The wooden fence around Femi's garden had decayed after years of rain.

intransitive: [subject] decayed over time

Talia's back teeth decayed because she rarely brushed before going to bed.

common collocation: teeth decayed

Common collocations
  • slowly decayed
  • gradually decayed
  • decayed over time
  • teeth decayed
  • wood decayed
Synonyms
  • rotted

    more specific to organic matter (wood, food, leaves)

  • deteriorated

    broader; works for health, materials, situations

  • crumbled

    implies physical breaking into small pieces

Antonyms
  • thrived

    for institutions, communities, or living things

  • strengthened

    for materials or abstract things like trust

Grammar Patterns

[subject] decayed

[agent] decayed [object]

Usage Note

Subject is typically physical (wood, metal, teeth, food, buildings) or abstract things that can weaken (trust, power, a relationship, an empire). Transitive use is less common than intransitive.

Common Mistakes

My phone decayed after one year.
My phone stopped working after one year.
use 'decayed' for slow biological rotting or long-term decline, not sudden breakdown of electronics.
I am decayed today.
I feel weak today.
'decayed' describes things or institutions, not a person's mood or short-term tiredness.

2. in physics, the unstable atoms inside a radioactive sample decayed when they bro

2.verbintransitiveC1
Definition

in physics, the unstable atoms inside a radioactive sample decayed when they broke apart on their own, turning into other elements and giving off radiation

Example

About half of the uranium sample decayed during the experiment in Lotte's lab.

intransitive: [radioactive substance] decayed

The carbon-14 atoms in the old bone had decayed enough to give a clear date.

scientific dating context

Common collocations
  • radioactive material decayed
  • decayed into
  • isotope decayed
  • atoms decayed
Synonyms
  • disintegrated

    common in physics writing; emphasises atoms breaking apart

Grammar Patterns

[radioactive substance] decayed (into [product])

Usage Note

Distinguish from sense 1: only sense 2 is used in physics, chemistry, and archaeology to describe atomic-level change. Subject must be a radioactive isotope, atom, or sample — not a building or relationship. Often followed by 'into' plus the resulting element.

Common Mistakes

The radio decayed in the basement.
The radioactive sample decayed in the basement.
sense 2 needs a radioactive subject; a household radio is sense 1 or just 'broke down'.

decayed — noun

Word family

Synonym discussion

Sense: verb/1

All four words describe something getting worse over time, but they fit different scenes. 'Rot' is the most everyday word and almost always refers to organic matter — food, leaves, wood — and carries a strong smell or visible mess. 'Decay' (and its participle 'decayed') is a touch more formal and stretches further: dentists talk about decayed teeth, archaeologists about decayed bones, and writers about decayed empires or moral standards. 'Deteriorate' is the broadest and most neutral, used for health, materials, and situations alike, but rarely for a single piece of food. 'Crumble' adds a physical image of something breaking into small pieces, often used for old walls or biscuits. So a slice of bread rots, an old castle crumbles, a patient's health deteriorates, and a forgotten village quietly decayed.

decay ↗rot ↗deteriorate ↗crumble ↗

Common collocations

Nouns

Adverbs

Phrases

  • signs of decayed
  • in a state of decayed
  • decayed over time
  • radioactive decayed

Prepositions

Etymology

LatinAnglo-NormanMiddle EnglishEnglish

Decayed comes from the verb 'decay', which entered English from Anglo-Norman 'decair' in the 1400s. The Anglo-Norman form itself goes back to Late Latin 'decadere', built from 'de-' (down, away) plus 'cadere' (to fall) — literally 'to fall away'. The same Latin root sits inside English 'cadence' and 'accident'. The physics meaning (atoms breaking down) is a much later, 20th-century extension once scientists needed a word for what radioactive substances do over time.