The phrase 'riot time' typically refers to a period of lawlessness, disorder and violence. The antonyms for 'riot' could be peace, calmness, harmony, tranquillity or order. Riot time can be quite devastating for the community, and synonyms for this phrase include mayhem, turmoil, chaos, and anarchy. The opposite of all of these descriptors would be peaceful, quiet, safe, and harmonious. When we think of a utopic society, it's one where there's never any riot time, where there's no threat of civil unrest or chaos. Antonyms for 'riot time' don't just imply an absence of discord, but indicate a positive environment where people can thrive and enjoy their lives without the fear of violence or destruction.