execration vs four-letter word

execration

noun
  • An act or instance of cursing; a curse dictated by violent feelings of hatred; an imprecation; an expression of utter detestation. 

  • That which is execrated; a detested thing. 

four-letter word

noun
  • A swear word or any words considered to be taboo in a given scenario (regardless of length of word). 

  • A reference to any of several of the strongest English swear words that are also four letters long, especially those composing the so-called seven dirty words. 

How often have the words execration and four-letter word occurred in a corpus of books? (source: Google Ngram Viewer )