The antonyms for the phrase "most cracking" may vary depending on the context in which it is used. However, some opposite words that can be used to replace "most cracking" are: worst, poorest, weakest, lousiest, unpleasant, and unsatisfactory. These words imply that the thing being described is far from being good or satisfactory, unlike "most cracking", which means impressive or exciting. For example, if someone says, "The party was the most cracking event of the year," the opposite statement would be, "The party was the worst event of the year." Therefore, it is essential to consider the context and tone of the sentence while choosing appropriate antonyms for "most cracking.