decay definition
To decay means to rot, decompose, break down. Our bodiesâanything organicâwill decay after death. Broken sidewalks, potholes, graffiti are all signs of urban decay. Tooth decay is something to avoid. Decay can also mean decline. Anyone, even a great athlete, must exercise regularly to maintain muscle toneâas soon as you stop, the muscles begin to decay. If the strength of the cable signal coming into your house grows weaker over time, you can complain that it has decayed.