To decay means to rot, decompose, break down. Our bodies—anything organic—will decay after death. Broken sidewalks, potholes, graffiti are all signs of urban decay. Tooth decay is something to avoid.

Decay can also mean decline. Anyone, even a great athlete, must exercise regularly to maintain muscle tone—as soon as you stop, the muscles begin to decay. If the strength of the cable signal coming into your house grows weaker over time, you can complain that it has decayed.

Definitions of decay

n the organic phenomenon of rotting

Type of:
organic phenomenon
(biology) a natural phenomenon involving living plants and animals

n an inferior state resulting from the process of decaying

“the corpse was in an advanced state of decay
“the house had fallen into a serious state of decay and disrepair”
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putrefaction, rot
a state of decay usually accompanied by an offensive odor
decomposition, disintegration
in a decomposed state
deterioration, impairment
a symptom of reduced quality or strength
the state of being rancid; having a rancid scent or flavor (as of old cooking oil)
the disintegration of social norms governing behavior and thought and social relationships
corruption, putrescence, putridness, rottenness
in a state of progressive putrefaction
a state of deterioration in metals caused by oxidation or chemical action
desolation, devastation
the state of being decayed or destroyed
decrepitude, dilapidation
a state of deterioration due to old age or long use
impairment resulting from long use
Type of:
a condition of damage or decay

n the process of gradually becoming inferior

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caries, cavity, dental caries, tooth decay
soft decayed area in a tooth; progressive decay can lead to the death of a tooth
decay of matter (as by rot or oxidation)
decomposition, putrefaction, rot, rotting
(biology) the process of decay caused by bacterial or fungal action
dilapidation, ruin
the process of becoming dilapidated
spoilage, spoiling
the process of becoming spoiled
mildew, mold, mould
the process of becoming mildewed
the process of becoming sour
Type of:
action, activity, natural action, natural process
a process existing in or produced by nature (rather than by the intent of human beings)

n a gradual decrease; as of stored charge or current

exponential decay, exponential return
a decrease that follows an exponential function
relaxation, relaxation behavior
(physics) the exponential return of a system to equilibrium after a disturbance
Type of:
decrease, decrement
a process of becoming smaller or shorter

n the spontaneous disintegration of a radioactive substance along with the emission of ionizing radiation

disintegration, radioactive decay
alpha decay
radioactive decay of an atomic nucleus that is accompanied by the emission of an alpha particle
beta decay
radioactive decay of an atomic nucleus that is accompanied by the emission of a beta particle
Type of:
nuclear reaction
(physics) a process that alters the energy or structure or composition of atomic nuclei

v undergo decay or decomposition

“The body started to decay and needed to be cremated”
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decompose, molder, moulder, rot
break down
go bad, spoil
become unfit for consumption or use
become putrid; decay with an offensive smell
melt away in the process of decay
break down naturally through the action of biological agents
suspend (meat) in order to get a gamey taste
become rotten
go bad or sour
Type of:
undergo a change; become different in essence; losing one's or its original nature

v fall into decay or ruin

“The unoccupied house started to decay
crumble, dilapidate
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become worse or disintegrate
corrode, rust
become destroyed by water, air, or a corrosive such as an acid
change under the action or influence of the weather
eat at, erode, gnaw, gnaw at, wear away
become ground down or deteriorate
droop, wilt
become limp
fall into ruin
break, bust, fall apart, wear, wear out
go to pieces
go to pot, go to the dogs
become ruined
eat away, fret
wear away or erode
wear, wear down, wear off, wear out, wear thin
deteriorate through use or stress
fray, frazzle
wear away by rubbing
Type of:
undergo a change; become different in essence; losing one's or its original nature

v lose a stored charge, magnetic flux, or current

decompose, disintegrate
cause to undergo fission or lose particles
Type of:
change integrity
change in physical make-up

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