accent has 10 distinct synonyms spread across 7 of its 7 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.
distinctive manner of oral expression
“he couldn't suppress his contemptuous accent”
special importance or significance
“the red light gave the central figure increased emphasis”
the usage or vocabulary that is characteristic of a specific group of people
“the immigrants spoke an odd dialect of English”
the relative prominence of a syllable or musical note (especially with regard to stress or pitch)
“he put the stress on the wrong syllable”
a diacritical mark used to indicate stress or placed above a vowel to indicate a special pronunciation
to stress, single out as important
“Dr. Jones emphasizes exercise in addition to a change in diet”
put stress on; utter with an accent
“In Farsi, you accent the last syllable of each word”
Synonyms, antonyms and the broader and narrower relations for accent come from Princeton University’s WordNet. Full sources and licences.