windage has 2 distinct synonyms spread across 2 of its 4 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.
the retarding force of air friction on a moving object
the space between the projectile of a smoothbore gun and the surface of the bore of the gun
exposure to the wind (as the exposed part of a vessel's hull which is responsible for wind resistance)
the deflection of a projectile resulting from the effects of wind
Synonyms, antonyms and the broader and narrower relations for windage come from Princeton University’s WordNet. Full sources and licences.