Extensive synonyms such as all-encompassing, ample, across the board, and all-embracing. Extensive is an adjective, and its antonyms are small and limited. Additionally, here are 42 synonyms, related words, and verbs for extensive.
ample, boundless, broad, capacious, commodious, considerable, expansive, great, huge, immeasurable, immense, large, large-scale, roomy, sizeable, spacious, substantial, sweeping, vast, and voluminous.