not worthy of reliance or trust; in the early 1950s computers were large and expensive and unreliable; an undependable assistant

[ Syn: undependable , undependable ]

liable to be erroneous or misleading; an undependable generalization

[ Syn: undependable ]

dangerously unstable and unpredictable; treacherous winding roads; an unreliable trestle

[ Syn: treacherous ]

lacking a sense of responsibility