dress up vs wear formal clothes

dress up

verb
  • To put on a costume portraying oneself as a particular type of character or well-known person. 

  • To present in a favorable light. 

  • To decorate; to prettify. 

  • To put on special or fancy clothes. 

  • To put a costume on (someone) portraying them as a particular type of character or well-known person. 

wear formal clothes

How often have the words dress up and wear formal clothes occurred in a corpus of books? (source: Google Ngram Viewer )