complication vs expression

complication

noun
  • The act or process of complicating. 

  • A person who doesn't fit in with the main scheme of things; an interloper. 

  • The state of being complicated; intricate or confused relation of parts; complexity. 

  • A feature beyond basic time display in a timepiece. 

  • A disease or diseases, or adventitious circumstances or conditions, coexistent with and modifying a primary disease, but not necessarily connected with it. 

expression

noun
  • (manufacturing) The act of pressing or squeezing out. 

  • A specific blend of whisky. 

  • A colloquialism or idiom. 

  • The action of expressing thoughts, ideas, feelings, etc. 

  • An arrangement of symbols denoting values, operations performed on them, and grouping symbols. 

  • The process of translating a gene into a protein. 

  • A facial appearance usually associated with an emotion. 

  • A particular way of phrasing an idea. 

  • A piece of code in a high-level language that returns a value. 

  • The tone of voice or sound in music. 

  • emotional involvement or engagement in a text read aloud rendered by the voice of the reciter or the reader 

How often have the words complication and expression occurred in a corpus of books? (source: Google Ngram Viewer )