middleperson vs operator

middleperson

noun
  • An intermediate dealer of any gender; a middleman or middlewoman. 

operator

noun
  • A person who is adept at making deals or getting results, especially one who uses questionable methods. 

  • A function or other mapping that carries variables defined on a domain into another variable or set of variables in a defined range. 

  • A telecommunications facilitator whose job is to establish temporary network connections. 

  • A kind of expression that enters into an a-bar movement dependency and is said to bind a variable. 

  • The administrator of a channel or network on IRC. 

  • A symbol that represents a construct in a programming language and differs from a normal function in its syntax. 

  • A member of a military special operations unit. 

  • The game of Chinese whispers. 

  • One who operates. 

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