/ ˌʌnrɪˈlaɪəbl; NAmE / adjective
that cannot be trusted or depended on :
The trains are notoriously unreliable.
He's totally unreliable as a source of information.
OPP reliable
► un·re·li·abil·ity / ˌʌnrɪˌlaɪəˈbɪləti; NAmE / noun [ U ]:
the unreliability of some statistics