A comprehensive analysis of the word mauha ("mystery") and its image in Anna Akhmatova's art demonstrates how insistently Akhmatova created an aura of mystery around her life. The intentional duality of her birth date; the modelling of the image of her childhood as a period when she became aware of her otherness; the legend of a precocious gift of vision and foresight, which is relevant to the image of Akhmatova's persona (Cassandra - Moon - Maiden enchantress -Chingisidess) and is also associated with the main spheres of her poetry: antiquity, the magical power of poetry, and history. The article identifies the actualisation of "Akhmatova's mystery" in different aspects: biographical, personally identificatory, and poetical proper. Rigorous linguistic analysis involving corpus--based data makes it possible to establish the special position the word mauha plays in Anna Akhmatova's vocabulary and provide a justification of its status as an idioglossia. The word mauha in Akhmatova's poems organises a wide thematical and associative field around itself, whose units are frequently used and assume an individual significance. The poems contain all meanings of the lexeme mauha that are used in the language system, and all the lexical-semantic variants are consolidated by the seme "unknown information". The invariant meaning of the word mauha is attributed to the opposition "knowledge - ignorance". The semantic complex of the lexeme in poetry is also strengthened by the meaning "arcane knowledge, involvement in mystery, and reaching the truth". It is established that the lexically invariable image of mauha, which can also be seen as a leitmotif, is found in all the themes conceptually significant for Akhmatova: destiny, art, and love. Only on one occasion is the image of mystery not marked by a word but instead grows out of the atmosphere of the poem, which is conterminous to secret fear and mystical terror. Secret as something irrational, inexplicably horrifying is almost certainly commonly found in poems about time and space, where the poet's daily life takes place. The fear of enclosed space and swift--flowing time is empowered by life circumstances, in which the poet's creative expression of will is materialised. This fear is born out of the primary knowledge of limits, beyond which a human being is not allowed to go. The analysis of the word mauha and its image in the poet's art leads the authors to conclude that the externally austere, but internally counterintuitive harmony of Anna Akhmatova's poetry is created along the fine line between the impermissible and the unrestricted, the secret and the explicit, the mystical and the rational.
