/ ˌʌnprɪˈdɪktəbl; NAmE / adjective
1.
that cannot be predicted because it changes a lot or depends on too many different things :
unpredictable weather
The result is entirely unpredictable.
2.
if a person is unpredictable , you cannot predict how they will behave in a particular situation
OPP predictable
► un·pre·dict·abil·ity / ˌʌnprɪˌdɪktəˈbɪləti; NAmE / noun [ U ]:
the unpredictability of the English weather
► un·pre·dict·ably adverb