We don't have synonyms for arethas yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are aretas and aretha.
(N) :
Arethas or Aretas was the leader of the Miaphysite Christian community of Najran in the early 6th century; he was executed during the persecution of Christians by king Yemen Yusuf As'ar Dhu Nuwas of Himyar in 523.
(N) :
Arethas or Aretas was the leader of the Miaphysite Christian community of Najran in the early 6th century; he was executed during the persecution of Christians by king Yemen Yusuf As'ar Dhu Nuwas of Himyar in 523.