Antonyms of adj predictable

1 sense of predictable

Sense 1
predictable (vs. unpredictable) -- (capable of being foretold)

unpredictable (vs. predictable) -- (not capable of being foretold)
        => aleatory -- (dependent on chance; "the aleatory element in life")
        => capricious, freakish -- (changeable; "a capricious summer breeze"; "freakish weather")
        => episodic, occasional -- (occurring or appearing at usually irregular intervals; "episodic in his affections"; "occasional headaches")
        => unforeseeable -- (incapable of being anticipated; "unforeseeable consequences")

Similarity of adj predictable

1 sense of predictable

Sense 1
predictable (vs. unpredictable) -- (capable of being foretold)
       => foreseeable -- (capable of being anticipated; "foreseeable costs were well within the budget")
       => inevitable -- (invariably occurring or appearing; "the inevitable changes of the seasons")
          Also See-> certain#4, sure#3