We don't have synonyms for hwang-ho yet — it may be a rare, specialized, newly coined, or misspelled word. The closest thesaurus entries we have are hwang ho and huang ho.
(n) :
Obsolete spelling of Huang He. [Synonym of Yellow River: a major river in northern China, passing through Qinghai, Sichuan, Gansu, Shaanxi, Shanxi, Henan and Shandong provinces as well as Ningxia and Inner Mongolia Autonomous Regions; the Mandarin Chinese-derived name.]
(n) :
Obsolete spelling of Huang He. [Synonym of Yellow River: a major river in northern China, passing through Qinghai, Sichuan, Gansu, Shaanxi, Shanxi, Henan and Shandong provinces as well as Ningxia and Inner Mongolia Autonomous Regions; the Mandarin Chinese-derived name.]