The present article examines a phenomenon of lexico-semantic duplicity in the context of teaching English as foreign language. The concept of duplicity, or variance, and in particular the stylistic differentiation of a lexeme, is opposed to the concept of an invariant, or the standard of literary language i.e. linguostylistic abstraction. The last one as in the context of teaching English as a foreign language by using authentic texts not only has a lingua-specific, but also a methodic significancy. In this way, an examination of writers' doublet pairs of words from the point of subjects as lexicology, history and stylistics allows to synthesize the differentiating features of the lexemes and to analyze the extent of the correlation between the variance meaning and the standard of the literary language i.e. linguostylistic abstraction.