walker has 9 distinct synonyms spread across 5 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.
New Zealand runner who in 1975 became the first person to run a mile in less that 3 minutes and 50 seconds (born in 1952)
a shoe designed for comfortable walking
a light enclosing framework (trade name Zimmer) with rubber castors or wheels and handles; helps invalids or the handicapped or the aged to walk
an enclosing framework on casters or wheels; helps babies learn to walk
Synonyms, antonyms and the broader and narrower relations for walker come from Princeton University’s WordNet. Full sources and licences.