Antonyms for the word "most permeating" are few and far between. The term permeating refers to something that penetrates deeply, spreads throughout or pervades entirely. Therefore, antonyms would include words that describe the opposite of these qualities, i.e., something that is confined, limited, localized, or restricted. A few examples of antonyms for "most permeating" might be things like scarce or limited, or words that imply a small, restricted influence or reach. However, these words may not capture the full sense of what "most permeating" means in a given context, and it is likely that synonyms or related terms would better express the intended sense.