cull vs repel

cull

verb
  • To pick or take someone or something (from a larger group). 

  • To select animals from a group and then kill them in order to reduce the numbers of the group in a controlled manner. 

  • To kill (animals etc). 

  • To lay off in order to reduce the size of, get rid of. 

  • To gather, collect. 

noun
  • A lobster having only one claw. 

  • A selection. 

  • An individual animal selected to be killed, or item of produce to be discarded. 

  • A piece unfit for inclusion within a larger group; an inferior specimen. 

  • An organised killing of selected animals. 

  • A fool, gullible person; a dupe. 

repel

verb
  • To reject, put off (a request, demand etc.). 

  • To ward off (a malignant influence, attack etc.). 

  • To drive back (an assailant, advancing force etc.). 

  • To cause repulsion or dislike in; to disgust. 

  • To save (a shot). 

  • To force away by means of a repulsive force. 

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