We don't have synonyms for chadar yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are chanar, chador and chamar.
(n) :
Alternative spelling of chador. [A loose robe made from a single cloth, worn as a combination head covering, veil and shawl by chiefly Muslim women (and occasionally by those of other faiths) in Iran and South Asia.]
(n) :
Alternative spelling of chador. [A loose robe made from a single cloth, worn as a combination head covering, veil and shawl by chiefly Muslim women (and occasionally by those of other faiths) in Iran and South Asia.]