illiterate vs soft-headed

illiterate

adj
  • Unable to read and write. 

  • Not conforming to prescribed standards of speech or writing. 

  • Having less than an expected standard of familiarity with language and literature, or having little formal education. 

  • Ignorant in a specified way or about a specified subject. 

noun
  • An illiterate person, one either not able to read and write or not knowing how. 

  • A person ignorant about a given subject. 

soft-headed

How often have the words illiterate and soft-headed occurred in a corpus of books? (source: Google Ngram Viewer )