1de·cay 
/dɪˈkeɪ/ verb
de·cays; de·cayed; de·cay·ing /dɪˈkeɪ/ verb 1 : to be slowly destroyed by natural processes : to be slowly broken down by the natural processes that destroy a dead plant or body [no obj] ▪ Tomatoes that fall off the vine will decay [=rot] on the ground. ▪ a dead fish decaying [=decomposing] on the beach ▪ the smell of decaying/decayed rubbish [+ obj] ▪ dead plants and leaves decayed by bacteria 2 [no obj] : to slowly lose strength, health, etc.
▪ She believes that the moral fiber of our society is decaying. ▪ our decaying public school system ▪ His mind/health is beginning to decay. [=decline] 3 [no obj] of a building, area, etc. : to go slowly from a bad condition to a worse condition : to slowly enter a state of ruin
▪ The city's neighborhoods are decaying.
▪ She believes that the moral fiber of our society is decaying. ▪ our decaying public school system ▪ His mind/health is beginning to decay. [=decline]
▪ The city's neighborhoods are decaying.
synonyms decay, decompose, rot, putrefy, and spoil mean to slowly fall apart and become destroyed by natural processes. decay is the most general of these terms. It often suggests a slow change from a state of strength or perfection.
▪ a decaying mansion decompose stresses that bacteria, worms, insects, etc., are destroying and breaking apart something that is dead. ▪ the animal's decomposing flesh ▪ Eventually the vegetation decomposes and is mixed with dirt and used in the garden. rot is a close synonym of decompose but also suggests a bad smell. ▪ Flies swarmed around the rotting fruit. putrefy is very similar to decompose and rot but is used to refer to dead people or animals and not to plants. It suggests that something is extremely unpleasant to see or smell. ▪ corpses putrefying on the battlefield spoil is used when talking about food that is no longer safe to eat. ▪ The meat will spoil if it is not kept cold.
▪ a decaying mansion decompose stresses that bacteria, worms, insects, etc., are destroying and breaking apart something that is dead. ▪ the animal's decomposing flesh ▪ Eventually the vegetation decomposes and is mixed with dirt and used in the garden. rot is a close synonym of decompose but also suggests a bad smell. ▪ Flies swarmed around the rotting fruit. putrefy is very similar to decompose and rot but is used to refer to dead people or animals and not to plants. It suggests that something is extremely unpleasant to see or smell. ▪ corpses putrefying on the battlefield spoil is used when talking about food that is no longer safe to eat. ▪ The meat will spoil if it is not kept cold.
