junior vs lastborn

junior

noun
  • A younger person. 

  • A junior barrister. 

  • A third-year student at a high school or university. 

  • A name suffix used after a son's name when his father has the same name (abbreviations: Jnr., Jr., Jun.). 

adj
  • Belonging to a younger person, or an earlier time of life. 

  • Low in rank; having a subordinate role, job, or situation. 

  • Younger. 

  • Of or pertaining to a third academic year in a four-year high school (eleventh grade) or university. 

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. 

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