Borderline

Adjective

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

Derived terms

 * borderline personality disorder

Noun

 * 1) A boundary or accepted division; a border.

Thesaurus
ambiguous, bordering, boundary, bounding, coastal, determinant, determinative, determining, dubitable, equivocal, extreme, fringing, frontier, limbic, liminal, limit, limiting, littoral, marginal, open, problematic, rimming, skirting, terminal, threshold, uncertain, unclear, undecided, unsettled