verb / noun
decay
dih-KAY/dɪkˈeɪ/
Gradual loss of soundness through breakdown.
The fallen apple shows decay in its collapsed, moldy flesh.

Etymology
The underlying image is “falling off”: a decline in strength, quality, or soundness. This general sense of deterioration later extended to physical decomposition and rotting.
In context
statues and monuments that will be around forever? We all know they'll decay into ruin over time.
More examples
- Dead leaves decay slowly on the forest floor.
- Regular brushing helps prevent tooth decay.
- The wooden steps have decayed after years of neglect.
Forms
decay · decays · decayed · decaying
Similar words
- rot
- Focuses on organic material becoming soft and breaking down.
- decompose
- Emphasizes organic matter breaking down into simpler substances.
- deteriorate
- Covers worsening condition or quality without necessarily involving rotting.