Existential loneliness is a topic of debate that has been explored over three centuries. Nineteenth-century novelists contributed to cognition-based existentialism in a way that has shaped our contemporary understanding and conceptualization. This study investigates the thematic coverage of existential loneliness explored by novelists, poets, and writers to make conclusions about the cross-cultural stylometric signature, the underlying conceptual metaphors, and the priming of each linguistic metaphor for the difficult-to-attain definition of existential loneliness. In the compiled literary corpus, loneliness is represented through 11 linguistic metaphors, the most frequent of which are “loneliness is unbearable hell”, “loneliness is harm”, “loneliness is internal trait”, “loneliness is inability to keep company”, and “loneliness is poverty of self”. The retrieved results are computationally compared to the literary works of the most influential existential writers. Thus, the Kazakh writer Nurgali Oraz is very diverse in terms of using loneliness-related conceptual metaphors, which unites him with such internationally recognized authors as Dostoyevsky, Tolstoy, Flaubert, Chekhov, Turgenev, and Proust.