debut has 5 distinct synonyms spread across 1 of its 5 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.
present for the first time to the public
“The band debuts a new song or two each month”
appear for the first time in public
“The new ballet that debuts next months at Covent Garden, is already sold out”
Synonyms, antonyms and the broader and narrower relations for debut come from Princeton University’s WordNet. Full sources and licences.
make one's debut
“This young soprano debuts next month at the Metropolitan Opera”
the act of beginning something new
“they looked forward to the debut of their new product line”
the presentation of a debutante in society