1. dissimilar Substances quite unlike are heterogeneous as regards each other. A heterogeneous mixture is one whose constituents are not only unlike in kind, but unevenly distributed; cement is composed of s Synonyms: heterogeneous, confused, mingled, unhomogeneous, conglomerate, miscellaneous, unlike, discordant, mixed, variant, dissimilar, non-homogeneous, various Antonyms: alike, homogeneous, identical, like, pure, same, similar, uniform