a spinster vs unwed

a spinster

unwed

adj
  • Not married. 

verb
  • To annul the marriage of. 

  • To separate. 

noun
  • One who is not married; a bachelor or a spinster. 

  • Should unweds living together receive the same social benefits as married couples? 

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