The answer to the crossword question “Spoil is ROT” is simply a definition. The word “spoiled” means to have gone bad, decayed or become rotten. The word “rot” is a synonym for decay or decomposition. Therefore, the statement “Spoil is ROT” is simply stating that when something has spoiled, it has decayed or become rotten, just like if something has begun to rot. The answer to this question is straightforward and doesn’t require extensive explanation.