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 for extensive and words similar to it.
Ample, boundless, broad, capacious, commodious, considerable, expansive, great, huge, immeasurable, immense, large, large-scale, roomy, sizeable, spacious, substantial, sweeping, vast, and voluminous.
Across the board, all-embracing, all-encompassing, all-inclusive, boundless, broad, catholic, complete, comprehensive, cross-disciplinary, exhaustive, interdisciplinary, multidisciplinary, profound, sweeping, thorough, universal, vast, wholesale, wide, and wide-ranging.