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.
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”
Synonyms, antonyms and the broader and narrower relations for cup come from Princeton University’s WordNet. Full sources and licences.