cat-o'-nine-tails vs flail

cat-o'-nine-tails

noun
  • A scourge (multi-tail whip) having nine, often knotted, whipcords, formerly used for flogging as naval punishment. 

  • A similarly constructed leather nine-tail whip, as used in British penal colonies and certain armies. 

flail

noun
  • A weapon which has the (usually spherical) striking part attached to the handle with a flexible joint such as a chain. 

  • A tool used for threshing, consisting of a long handle with a shorter stick attached with a short piece of chain, thong or similar material. 

verb
  • To beat using a flail or similar implement. 

  • To wave or swing vigorously 

  • To thresh. 

  • To move like a flail. 

How often have the words cat-o'-nine-tails and flail occurred in a corpus of books? (source: Google Ngram Viewer )