wall has 7 distinct synonyms spread across 3 of its 9 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.
an architectural partition with a height and length greater than its thickness; used to divide or enclose an area or to support another structure
“the south wall had a small window”
Synonyms, antonyms and the broader and narrower relations for wall come from Princeton University’s WordNet. Full sources and licences.
anything that suggests a wall in structure or function or effect
“a wall of water”
(anatomy) a layer (a lining or membrane) that encloses a structure
“stomach walls”
a difficult or awkward situation
“his back was to the wall”
a vertical (or almost vertical) smooth rock face (as of a cave or mountain)
a layer of material that encloses space
“the walls of the cylinder were perforated”
a masonry fence (as around an estate or garden)
“the wall followed the road”
an embankment built around a space for defensive purposes
“they stormed the ramparts of the city”