predictor has 3 distinct synonyms spread across 1 of its 3 senses. Each sense below keeps its own list, because a synonym belongs to a meaning and not to a word: swapping one sense's substitute into another sense's sentence is how a thesaurus makes writing worse. WordNet records no antonym for it — antonymy is a relation between word forms rather than concepts, so it is deliberately sparse.
Counts are distinct word forms across every sense. A synonym that appears under three senses is counted once here and shown three times below, under each sense it belongs to.
someone who makes predictions of the future (usually on the basis of special knowledge)
information that supports a probabilistic estimate of future events
“the weekly bulletin contains several predictors of mutual fund performance”
a computer for controlling antiaircraft fire that computes the position of an aircraft at the instant of a shell's arrival
Synonyms, antonyms and the broader and narrower relations for predictor come from Princeton University’s WordNet. Full sources and licences.