Dissimilarity, unlikeness, difference, divergence, divergency, distinction are comparable when they mean lack of agreement or correspondence (or an instance of such lack) in appearance, in qualities, or in nature brought out by a comparison of two or more things.
Dissimilarity and unlikeness, the most general terms in this group, are often used interchangeably without loss, but when there is little basis for comparison and the contrast is obvious, dissimilarity is usually preferred.
Unlikeness is commonly the preferred term, however, when the things contrasted belong to a common category, and there are fundamental likenesses between them.
Difference suggests notice of a quality or feature which marks one thing as apart from another. The term may imply want of resemblance in one or more particulars or want of identity or a disagreement or cause of disagreement which separates individuals or makes them hostile to each other.
Divergence or divergency applies to a difference between things or less often persons having the same origin, the same ends, or the same background or belonging to the same type or class; there is usually an implication of a difference that makes for cleavage or increasing unlikeness.
Distinction usually implies want of resemblance in detail, especially in some minute or not obvious detail; it therefore commonly applies to a difference that is brought out by close observation, study, or analysis or that marks the line of division between two like things.