不可靠的，靠不住的，不可信赖的；

1. 难凭：难平息的inappeasable | 难凭undependable | 难取悦的fastidiousfussy

1. not worthy of reliance or trust

    e.g. in the early 1950s computers were large and expensive and unreliable
           an undependable assistant

    Synonym: unreliable

2. liable to be erroneous or misleading

    e.g. an undependable generalization

    Synonym: unreliable