liner has 3 distinct synonyms spread across 4 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.
(baseball) a hit that flies straight out from the batter
“the batter hit a liner to the shortstop”
a protective covering that protects an inside surface
Synonyms, antonyms and the broader and narrower relations for liner come from Princeton University’s WordNet. Full sources and licences.
a piece of cloth that is used as the inside surface of a garment
a large commercial ship (especially one that carries passengers on a regular schedule)