lastborn vs youthful

lastborn

adj
  • Younger than anyone else in a group. 

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

noun
  • The youngest child of a family. 

  • The youngest member of any company or organization. 

youthful

adj
  • Characteristic of young people. 

  • Young or seeming young. 

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