border vs borderline

border

verb
  • To form a border around; to bound. 

  • To approach; to come near to; to verge (with on or upon). 

  • To put a border on something. 

  • To touch at a border (with on, upon, or with). 

  • To lie on, or adjacent to, a border of. 

noun
  • A string that is both a prefix and a suffix of another particular string. 

  • The outer edge of something. 

  • A strip of ground in which ornamental plants are grown. 

  • border morris or border dancing; a vigorous style of traditional English dance originating from villages along the border between England and Wales, performed by a team of dancers usually with their faces disguised with black makeup. 

  • The line or frontier area separating political or geographical regions. 

  • A decorative strip around the edge of something. 

borderline

verb
  • To border, or border on; to be physically close or conceptually akin to. 

adj
  • Showing bad taste. 

  • Nearly; not clearly on one side or the other of a border or boundary, ambiguous. 

  • Exhibiting borderline personality disorder. 

adv
  • Nearly; not entirely but nevertheless to a great extent. 

noun
  • A boundary or accepted division; a border. 

  • An individual who has borderline personality disorder. 

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