1. 不可靠的;不能信赖的
If you describe a person, machine, or method as unreliable, you mean that you cannot trust them.

1. not worthy of reliance or trust

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

Synonym: undependable

2. liable to be erroneous or misleading

e.g. an undependable generalization

Synonym: undependable

3. lacking a sense of responsibility

4. dangerously unstable and unpredictable

e.g. treacherous winding roads
an unreliable trestle

Synonym: treacherous