The paper focuses on relations between word-formation and morphemic structure of a Slovak word based on the material from Slovník koreňových morfém slovenčiny [Slovak Dictionary of Root Morphemes] (Sokolová et al., 2012). Particularly, manifestations of morphemic variation determined by word-formation poly-motivation are analysed. Poly-motivation arises from the re-grouping of the relations within a word-formation nest, where the mediated motivation can be understood as an alternative direct motivation, e.g. aerodynamika [noun, ‘aerodynamics’] → (aerodynamický [adjective, ‘related to aerodynamics’]) → aerodynamicky [adverb]. The adverb aerodynamicky is derived from the adjective (aerodynamický → aerodynamick-y ‘in an aerodynamic manner’) as well as from the noun (aerodynamika → aerodynamic-ky ‘with regard to aerodynamics’). Thus, the structure of affixes can be extended as a result of infixation conditioned by poly-motivation, cf. aerodynamick-y (suffix -y) / aerodynamic-ky (suffix -y with an infix: -k:y). As far as poly-motivation is concerned, a particular affix can have several morphemic and word-formation manifestations, e.g. Slovak adverb suffix -y can be manifested as -y, -ky, -icky, -isticky, -sky, -euticky, -aticky, -eticky, -ecky, -nícky.
