When something decays it becomes rotten. It goes from good to bad. Something must be done to prevent or get rid of the decay, or else the thing will have to be removed. This word can be used as a verb or as a noun.
Old buildings decay if they are not maintained. (verb)
It’s cost effective to prevent the decay of old buildings. (noun)
Some neighborhoods in American cities have decayed because of neglect. (This verb is in the present perfect tense.)
Decaying neighborhoods left unchecked create problems for residents. (The word "decaying" is an adjective.)
Urban decay results in increased crime rates.
Tooth decay results in cavities.
Teeth that have too much decay might have to be removed.
To prevent your teeth from decaying, you have to brush and floss regularly.
When wood is constantly exposed to water, it can begin to decay and rot.
To prevent wood from decaying, it should be kept dry and treated with some kind of preservative.
There are some areas of my house that have begun to decay and must be replaced.
Some people say that American democracy is in decay.
Democracies begin to decay when citizens allow their leaders to openly lie, cheat, and steal.
Education can help prevent the decay of a democracy.