SWAT vs pile-up

SWAT

noun

  • A SWAT team 

pile-up

noun

  • A pile of tackling players. 

  • An accumulation that occurs over time, especially one which is not welcome. 

  • A pile of crashed vehicles due to a traffic accident. 

How often have the words SWAT and pile-up occurred in a corpus of books? (source: Google Ngram Viewer )