Decisively rhymes with:
aggressively, cohesively, comprehensively, compulsively, conclusively, defensively, derisively, effusively, excessively, exclusively, expensively, explosively, extensively, impassively, impressively, impulsively, inconclusively, inexpensively, intensively, massively, obsessively, offensively, passively, persuasively, progressively, reflexively, successively
Decisively sounds like:
dashville, decibel, decouple, detachable, disable, disciple, dishevel, dispel, dispell, display, dixville