flail vs swingle

flail

verb
  • To wave or swing vigorously 

  • To beat using a flail or similar implement. 

  • To thresh. 

  • To move like a 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. 

swingle

verb
  • To dangle; to wave hanging. 

  • To beat or flog, especially for extracting the fibres from flax stalks; to scutch. 

noun
  • The swinging part of a flail, especially that which is used on the grain in threshing; the swiple. 

  • An implement used to separate the fibres of flax by beating them; a scutch. 

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