cup has 3 distinct synonyms spread across 3 of its 11 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.
Synonyms, antonyms and the broader and narrower relations for cup come from Princeton University’s WordNet. Full sources and licences.
any cup-shaped concavity
“bees filled the waxen cups with honey”
a United States liquid unit equal to 8 fluid ounces
cup-shaped plant organ
a punch served in a pitcher instead of a punch bowl
the hole (or metal container in the hole) on a golf green
“he swore as the ball rimmed the cup and rolled away”
a large metal vessel with two handles that is awarded as a trophy to the winner of a competition
“the school kept the cups is a special glass case”
form into the shape of a cup
“She cupped her hands”