When food goes stale, it loses its freshness and becomes less appealing to eat. There are many synonyms for this phenomenon, including: becomes rancid, spoils, turns bad, deteriorates, goes off, grows old, becomes moldy, decays, rots, stalemates, gets musty, and curdles. These words can apply to different foods and circumstances - from bread becoming moldy, to milk curdling, to chips becoming stale. By using different synonyms for "going stale," writers and speakers can add variety and specificity to their language, while accurately conveying the concept of food losing its freshness and appeal.