Unresemblance is a word that describes the lack of similarity or resemblance between two objects or persons. It is a relatively uncommon word, and as such, it can be challenging to find suitable synonyms that adequately convey the same meaning. However, some synonyms that can be used in place of unresemblance include unlikeness, dissimilarity, disparity, difference, and diversity. Other synonyms that could be used include nonconformity, distinctiveness, heterogeneity, contrast, and variation. When it comes to expressing a lack of similarity, any of these synonyms could be used in place of unresemblance, depending on the specific context and tone the writer or speaker wishes to convey.