between two different conditions, with the possibility of belonging to either one of them

Only in borderline cases (= cases where students might succeed or fail) will pupils have an oral exam. 只有在处于及格边缘的情况下小学生才会有口试。

She was a borderline candidate for the job. 她是个不上不下的候选人。

Synonym: marginal

something that separates two different qualities

The borderline between friendship and intimacy is often hard to define. 友谊和亲昵关系之间的界线常常很难界定。

See also: border noun