mile has 15 distinct synonyms spread across 6 of its 8 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.
a unit of length equal to 1,760 yards or 5,280 feet; exactly 1609.344 meters
a unit of length used in navigation; exactly 1,852 meters; historically based on the distance spanned by one minute of arc in latitude
a large distance
“he missed by a mile”
a former British unit of length once used in navigation; equivalent to 6,000 feet (1828.8 meters)
a former British unit of length equivalent to 6,080 feet (1,853.184 meters); 800 feet longer than a statute mile
a footrace extending one mile
“he holds the record in the mile”
Synonyms, antonyms and the broader and narrower relations for mile come from Princeton University’s WordNet. Full sources and licences.