Decay
/dɪˈkeɪ/
noun
The process or result of being gradually decomposed.
A deterioration of condition; loss of status or fortune.
verb
To deteriorate, to get worse, to lose strength or health, to decline in quality.
“The pair loved to take pictures in the decaying hospital on forty-third street.”
(of organic material) To rot, to go bad.
“The cat's body decayed rapidly.”
(of an unstable atom) To change by undergoing fission, by emitting radiation, or by capturing or losing one or more electrons.