CHALK AND CHEESE

If we say that two people, or things, are like chalk and cheese, we mean that they are completely different from each other.

 Examples:

 “Airbnb and Uber are chalk and cheese”

 “Me and my brother are autistic, and - as my mother would say - we are chalk and cheese.”

 “‘Even though they are half-brothers, they are chalk and cheese,’ she says of the two horses. ‘This one needs a lot of motivation, a bit like a labrador.’”


 Why chalk and cheese?
 Although chalk and cheese may appear similar, they have completely different properties [1]; hence, this idiom is often used to refer to two people or things of the same type that have different characteristics, as in the above examples.


 Photo credit: poppet with a camera (Creative Commons)

 [1] “chalk” in Oxford Dictionary of English Idioms, edited by Ayto, John. Oxford University Press, 2009.