Here's what rhymes with divisiveness.

Consider these alternatives

disunity / unity factionalism / given partisanship / which antagonism / given sectarianism / given acrimony / testimony polarisation / education recrimination / information antagonisms / conditions cynicism / given inclusiveness / exclusiveness sectionalism / given fanaticism / position polarization / organization stereotyping / writing politicization / information sensationalism / given fratricide / side fratricidal / vital disorganization / organization