Antonyms of noun probability

1 of 2 senses of probability

Sense 2
probability -- (the quality of being probable; a probable event or the most probable event; "for a while mutiny seemed a probability"; "going by past experience there was a high probability that the visitors were lost")
       Antonym of improbability (Sense 1)
      => improbability, improbableness -- (the quality of being improbable; "impossibility should never be confused with improbability"; "the improbability of such rare coincidences")

Synonyms/Hypernyms (Ordered by Estimated Frequency) of noun probability

2 senses of probability

Sense 1
probability, chance -- (a measure of how likely it is that some event will occur; a number expressing the ratio of favorable cases to the whole number of cases possible; "the probability that an unbiased coin will fall with the head up is 0.5")
       => measure, quantity, amount -- (how much there is or how many there are of something that you can quantify)

Sense 2
probability -- (the quality of being probable; a probable event or the most probable event; "for a while mutiny seemed a probability"; "going by past experience there was a high probability that the visitors were lost")
       => quality -- (an essential and distinguishing attribute of something or someone; "the quality of mercy is not strained"--Shakespeare)