filling has 4 distinct synonyms spread across 2 of its 6 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.
a food mixture used to fill pastry or sandwiches etc.
(dentistry) a dental appliance consisting of any of various substances (as metal or plastic) inserted into a prepared cavity in a tooth
“when he yawned I could see the gold fillings in his teeth”
the act of filling something
Synonyms, antonyms and the broader and narrower relations for filling come from Princeton University’s WordNet. Full sources and licences.