vast
astronomical, boundless, colossal, elephantine, enormous, extensive, gigantic, ginormous (informal) great, huge, humongous or humungous (U.S. slang) illimitable, immeasurable, immense, limitless, mammoth, massive, measureless, mega (slang) monstrous, monumental, never-ending, prodigious, sweeping, tremendous, unbounded, unlimited, vasty (archaic) voluminous, wide
Antonyms
bounded, limited, microscopic, narrow, negligible, paltry, puny, small, tiny, trifling