This paper examines expressive sentences in Polish, such as Idiota, nie kierowca! (lit. idiot, not driver) ‘an idiot of a driver’ and Potwór, nie matka! (lit. monster, not mother) ‘a monster of a mother’. Variants of the “X, not Y” construction, its optional and obligatory elements are identified. Differences are emphasised between the emphatic “X, not Y construction” and non-emphatic negative copular clauses. Moreover, relatedness is discussed between expressive NN juxtapositions, such as kierowca idiota (lit. driver idiot) ‘an idiot of a driver’ or matka potwór (lit. mother monster) ‘a monster of a mother’, and the “X, not Y” construction. Semantic-structural types of expressive NN juxtapositions are considered, following the cross-linguistic classification of multiword units proposed by Scalise and Bisetto (2009). The reversibility of NN juxtapositions is taken into account as well. The question is addressed which types of juxtapositions allow their constituents to appear in the “X, not Y” construction.