Nouns

(n)decaythe process of gradually becoming inferior
(n)decay, declinea gradual decrease; as of stored charge or current
(n)decay, decompositionthe organic phenomenon of rotting
(n)decayan 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”
(n)decay, radioactive decay, disintegrationthe spontaneous disintegration of a radioactive substance along with the emission of ionizing radiation

Verbs

(v)disintegrate, decay, decomposelose a stored charge, magnetic flux, or current“the particles disintegrated during the nuclear fission process”
(v)decay, crumble, dilapidatefall into decay or ruin“The unoccupied house started to decay”
(v)decayundergo decay or decomposition“The body started to decay and needed to be cremated”