Source : WordNet®

undependable
     adj 1: not worthy of reliance or trust; "in the early 1950s
            computers were large and expensive and unreliable";
            "an undependable assistant" [syn: {unreliable}] [ant:
            {reliable}, {reliable}]
     2: not to be trusted [syn: {unreliable}]
     3: liable to be erroneous or misleading; "an undependable
        generalization" [syn: {unreliable}]