croak vs string up

croak

verb
  • To kill someone or something. 

  • To complain; especially, to grumble; to forebode evil; to utter complaints or forebodings habitually. 

  • To die. 

  • To utter in a low, hoarse voice. 

  • To make a croak. 

  • To make its sound. 

noun
  • The call of a frog or toad. (see also ribbit) 

  • A faint, harsh sound made in the throat. 

  • The harsh call of various birds, such as the raven or corncrake, or other creatures. 

string up

verb
  • To kill (a person) by hanging, especially to lynch. 

  • To concatenate; to link in a line. 

  • To suspend by means of rope, cord or similar material. 

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