Definitively rhymes with:
competitively, intuitively, sensitively, accumulatively, actively, administratively, affectively, affirmatively, alternatively, appreciatively, assertively, attentively, attractively, authoritatively, collectively, comparatively, competitively, consecutively, conservatively, constructively, cooperatively, creatively, cumulatively, deceptively, distinctively, effectively, exhaustively, figuratively, furtively, imaginatively, instinctively, intuitively, legislatively, negatively, objectively, positively, preemptively, proactively, productively, prohibitively, prospectively, protectively, provocatively, qualitatively, relatively, respectively, retroactively, retrospectively, seductively, selectively, sensitively, substantively, tentatively