We don't have synonyms for dead name yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are dead time, bad name and deadname.
(n) :
Alternative form of deadname. [(neologism, especially LGBTQ) A previous name of a person (especially a transgender person) who has since changed their name.]
(v) :
Alternative form of deadname. [(transitive) To refer to someone (especially a transgender person) who has changed names by a previous name.]
(n) :
Alternative form of deadname. [(neologism, especially LGBTQ) A previous name of a person (especially a transgender person) who has since changed their name.]
(v) :
Alternative form of deadname. [(transitive) To refer to someone (especially a transgender person) who has changed names by a previous name.]