threepenny vs unimportant

threepenny

adj
  • Of little worth; mean; vulgar. 

  • Having a value or cost of threepence. 

noun
  • A stamp worth three pence. 

unimportant

adj
  • petty; not important or noteworthy 

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