like chalk and cheese vs variant

like chalk and cheese

variant

noun
  • Something that is slightly different from a type or norm. 

  • A different sequence of a gene (locus). 

  • A variable that can hold any of various unrelated data types. 

  • One of a set of words or other linguistic forms that conveys the same meaning or serves the same function. 

adj
  • Showing deviation or disagreement. 

  • Showing variety, diverse. 

  • Covariant and/or contravariant. 

How often have the words like chalk and cheese and variant occurred in a corpus of books? (source: Google Ngram Viewer )