SIWASH Meaning of SIWASH in English [ 'sʌɪwɒʃ ]■ noun derogatory1》 an American Indian of the northern Pacific coast. 2》 another term for Chinook Jargon .OriginChinook Jargon, from Canad. Fr. sauvage 'wild'. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004