[adj] not worthy of reliance or trust; "in the early 1950s computers were large and expensive and unreliable"; "an undependable assistant"
[adj] liable to be erroneous or misleading; "an undependable generalization"
[adj] lacking a sense of responsibility
[adj] dangerously unstable and unpredictable; "treacherous winding roads"; "an unreliable trestle"
[adj] not to be trusted