OSSI Meaning of OSSI in English [ 'ɒsi ]■ noun ( plural ~es or ~s ) informal, often derogatory (in Germany) a citizen of the former German Democratic Republic.OriginGer., prob. an abbrev. of Ostdeutsche 'East German'. Concise Oxford English vocab. Сжатый оксфордский словарь английского языка. 2004