The phrase "most unslaked" refers to something that has not been satisfied, quenched or fulfilled. The antonyms for this phrase, therefore, would be words that express the opposite sentiment: satisfied, fulfilled, quenched, contented, gratified, sated, and appeased. These words indicate a sense of completion, contentment or satisfaction, whereas "most unslaked" implies a sense of restlessness, longing or unfulfilled desire. By contrasting these ideas, we can more deeply understand the nuances of language and the power of word choice to convey different emotions and ideas.