pitch has 28 distinct synonyms spread across 16 of its 23 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.
fall or plunge forward
“She pitched over the railing of the balcony”
set to a certain pitch
“He pitched his voice very low”
hit (a golf ball) in a high arc with a backspin
lead (a card) and establish the trump suit
set the level or character of
“She pitched her speech to the teenagers in the audience”
the property of sound that varies with variation in the frequency of vibration
Synonyms, antonyms and the broader and narrower relations for pitch come from Princeton University’s WordNet. Full sources and licences.
a vendor's position (especially on the sidewalk)
“he was employed to see that his paper's news pitches were not trespassed upon by rival vendors”
promotion by means of an argument and demonstration
a sports field with predetermined dimensions for playing soccer
an all-fours game in which the first card led is a trump
the action or manner of throwing something
“his pitch fell short and his hat landed on the floor”