Borderline/ˈbɔːrdərlaɪn/ Definition 1 of 3Pro Tip 1/3Almost Sufficient Use 'borderline' to describe something barely meeting a standard or requirement. His effort in the project was borderline acceptable. Pro Tip 2/3Emphasize Uncertainty Convey that a situation or quality is uncertain or may change with 'borderline'. Her attendance is borderline; she might fail due to absences. Pro Tip 3/3Indecisive Descriptor 'Borderline' expresses indecision between two options or categories. The movie is borderline horror or thriller, hard to categorize.