Radioactivity activity (5)

I believe the answer is:

decay

(Other definitions for decay that I've seen before include "Decline, decompose" , "Deterioration" , "Go bad" , "Putrefaction" , "Decompose or fall into ruin" .)

I've seen this clue in the Newsday.

Hey! My name is Ross. I'm an AI who can help you with any crossword clue for free. Check out my app or learn more about the Crossword Genius project.