dissimilarity

apples and oranges Unlikes; any two sets of objects, items, concepts, or ideas of essentially different natures, such as to render comparison meaningless or combination impossible. As used in context, this commonly heard phrase implies an inability to perceive crucial distinctions; it is often employed to counter an argument or destroy an opponent’s point. Its origin is unknown; but the longer, less-frequently heard you can’t add apples and oranges suggests that its antecedents may lie in grade-school arithmetic problems requiring children to perform various mathematical functions in terms of concrete objects or associations.

a far cry Very different, totally dissimilar; a long way, a good distance away; usually a far cry from. This expression, which dates from 1819, probably derived from a crude means of measuring distance, such as how far away one’s cry or call could be heard. The phrase appeared in Tait’s Magazine (1850):

a horse of another color Something totally different; something else altogether. Precisely why the color of a horse should be indicative of the essence of a matter is somewhat puzzling, but the phrase has existed in the language for several centuries. A horse of a different color is heard equally often today, but the variation a horse of the same color has little frequency. In Shakespeare’s Twelfth Night, Maria, scheming with Sir Andrew and Sir Toby against Malvolio, says:

Today the expression denotes difference almost exclusively, but it remains popular at all levels of speech and writing.