go-between vs procuress

go-between

noun
  • An intermediary or middleman. 

  • A shogi piece, used in chu shogi and larger shogi variants, that can move one step straight forward or straight backwards. 

procuress

noun
  • A middlewoman : a woman who performs as a go-between, an intermediary. 

  • A female procurer. 

How often have the words go-between and procuress occurred in a corpus of books? (source: Google Ngram Viewer )