noun. A line that establishes or marks a border.

noun. An indefinite area intermediate between two qualities or conditions.

adjective. undefined

adjective. Verging on a given quality or condition.

adjective. Of a questionable nature or quality.

adjective. Relating to a personality disorder characterized by a long-standing pattern of instability in interpersonal relationships, behavior, mood, and self-image that can interfere with social or occupational functioning or cause extreme emotional distress.

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

adjective. Showing bad taste.

noun. A boundary or accepted division; a border.

noun. a line that indicates a boundary

adjective. of questionable or minimal quality

"The term borderline has come into increasing use in the last thirty years, in describing a severe form of psychopathology."

minimal  minimum  

borderline personality disorder  

antisocial  autistic  delusional  homicidal  hypertensive  

ambiguous  bordering  boundary  bounding  coastal