Adjective

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

   He is borderline hypoglycemic and needs to monitor his sugar intake.

   I would rather hire a talented layman than a university graduate with borderline qualifications.

2. Showing bad taste.

   Your borderline remarks about my aunt's dress destroyed my evening.

Noun

1. A boundary or accepted division; a border.

   She lives on the borderline between reality and madness.