A fairly narrow line or space forming a boundary
A transitional interval beyond which some new action or different state of affairs is likely to begin or occur
Not affording certainty
Still borderline on the killing.
All five of the death dealers were borderline about abandoning Gabriel.
After this a peace was arranged by Nebuchadrezzar of Babylon and Syennesis of Cilicia, recognizing the Halys as the borderline.
Dean was wise enough not to ask what guise Fred used to cover his snoopingâ€”surely a technique borrowed from a mystery book hero and borderline illegal.