The word "peakiest" is an adjective that describes something as having the highest or most prominent point. Some synonyms for "peakiest" include "highest," "topmost," "cresting," "summiting," or "culminating." These words all denote a sense of being at the pinnacle or peak of something. Other related words may include "acerb," "acrid," "bitter," or even "acerbic," which all suggest a sharpness or intensity in either taste or personality. When describing mountains or other topographical features, words like "alpine," "hilly," or "mountainous" might also be appropriate synonyms for "peakiest." Ultimately, the choice of synonym should be based on context and the intended tone or emphasis of the language being used.