sandbag has 3 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.
Synonyms, antonyms and the broader and narrower relations for sandbag come from Princeton University’s WordNet. Full sources and licences.
downplay one's ability (towards others) in a game in order to deceive, as in gambling
protect or strengthen with sandbags; stop up
“The residents sandbagged the beach front”
a bag filled with sand; used as a weapon or to build walls or as ballast