Английский разговорный словарь (основной) - rare adjective (youth culture)

In young people's slang: extremely good or impressive; 'hip', 'cool'. Etymology: A revival of a colloquial sense of the adjective rare which first developed in the fifteenth century, but was considered archaic in the early twentieth century. The usage probably found its way into young people's slang through US Black street slang and rap. 'Rare!' is an expression of wonder, gasped rather than spoken. New Statesman 16 Feb. 1990, p. 12