ball sack vs shirk

ball sack

noun
  • An objectionable person (especially a man). 

  • The scrotum. 

shirk

noun
  • One who shirks, who avoids a duty or responsibility. 

  • The unforgivable sin of idolatry. 

verb
  • To avoid, especially a duty, responsibility, etc.; to stay away from. 

  • To evade an obligation; to avoid the performance of duty, as by running away. 

  • To procure by petty fraud and trickery; to obtain by mean solicitation. 

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