decay
/di-ˈkā/
verb
to undergo decomposition
to decline in health, strength, or vigor
to fall into ruin
decaying fruit
noun
rot; specifically : aerobic decomposition of proteins chiefly by bacteria
the product of decay
gradual decline in strength, soundness, or prosperity or in degree of excellence or perfection
The material is … resistant to fire, decay and termites …
tooth decay
noun
a radioactive nuclear transformation governed by the weak force in which a nucleon (such as a neutron) changes into a nucleon (such as a proton) of the other type with the emission of either an electron and an antineutrino or a positron and a neutrino