Synonyms of unpredictable in English:

unpredictable


See US English definition of unpredictable

See UK English definition of unpredictable

See Spanish definition of imprevisible

adjective

1‘the unpredictable results of the first-past-the-post system’

SYNONYMS
unforeseeable, undivinable, incalculable, uncertain, unsure, doubtful, dubious, in the balance, up in the air, random, arbitrary
informal iffy, hit and miss
ANTONYMS

predictable

2‘the men in here are unpredictable, violent, and dangerous’

SYNONYMS
erratic, moody, volatile, unstable, fickle, capricious, whimsical, temperamental, mercurial, changeable, variable, inconstant, undependable, unreliable, unmanageable, impulsive
ANTONYMS

predictable, reliable