From proportionnable + -ment. IPA(key): /pʁɔ.pɔʁ.sjɔ.na.blə.mɑ̃/ <span class="searchmatch">proportionnablement</span> proportionably...
From proportion + -able. proportionnable (plural proportionnables) proportionable <span class="searchmatch">proportionnablement</span>...