lastborn vs premature

lastborn

noun
  • The youngest child of a family. 

  • The youngest member of any company or organization. 

adj
  • Born last in a family; youngest in a the family. 

  • Younger than anyone else in a group. 

premature

noun
  • An infant born prematurely. 

adj
  • Taking place earlier than anticipated, prepared for, or desired. 

  • Suffering from premature ejaculation. 

  • Occurring before a state of readiness or maturity has arrived. 

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