shithead vs wild card

shithead

noun
  • A card game, the aim of which is to lose one's cards. 

  • A stupid or contemptible person. 

wild card

noun
  • A card that can be assigned any value or used to substitute for any needed card. 

  • A competitor or team that is allowed to compete in a tournament despite not reaching the normal standards to qualify for inclusion. 

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