quid pro quo vs swap out

quid pro quo

noun
  • Something which is offered or asked for in exchange for something else. 

  • An equal or fair transaction or series of process of exchange transactions; tit for tat. 

  • Something which is understood as something else; an equivocation. 

  • Substitution of one drug for another. 

  • A usually non-monetary exchange transaction, or series or process of exchange transactions. 

  • Sexual harassment in which a person in a workplace implicitly or explicitly requires sexual favours in exchange for something. 

swap out

noun
  • Anything that is swapped out for another; an exchange. 

  • A pre-prepared food item used in place of an unfinished food item in order to cut down the overall preparation time during filming. 

verb
  • To exchange (something) for (something else). (usually followed by with or for) 

  • To transfer (memory contents) into a swap file. 

  • To exchange (something or someone) for an unused (or less-used) equivalent. 

How often have the words quid pro quo and swap out occurred in a corpus of books? (source: Google Ngram Viewer )