The word "most frigorific" refers to the coldest or most freezing temperature. Antonyms for this word could include "warmest," "hottest," "tropical," or "blazing." These words are used to describe high temperatures or climates, rather than low ones. "Mild" and "temperate" are other antonyms, indicating a moderate or pleasant temperature. Additionally, "comfortable," "cozy," and "pleasant" are words that are used to describe comfortable temperatures, as opposed to frigorific conditions. These antonyms are often used in different contexts, such as weather forecasts, descriptions of clothing items or even food and beverages.