The term leviathan refers to something large or massive in size. Therefore, the antonyms for the word most leviathan would refer to something small or diminutive. Some possible antonyms include tiny, minuscule, petite, puny, insignificant, or microscopic. Alternatively, antonyms could focus on attributes beyond size, such as fragility, delicacy, or lightness. Examples of these antonyms included frail, delicate, airy, and weightless. The choice of the antonym will depend on the context in which it is used, and the intended meaning that the author wants to convey.