The paper offers a new etymology of the Old Ukrainian hydronym Slovuta and its derivational congeners Slovuticь and Slovutičь against the background of the non-Slavic equivalent Dъněprъ and the Greek transcriptions Δάναπρις and Βορυσϑένης. The proposed explication of OU Slovuta is undertaken in the context of research on «Old European» hydronymy as first introduced within Krahe’s school of thought. The author substantiates the origins of the derivative Slovuticь / Slovutičь in the historical paratactic construction Dъneprъ-Slovuticь. A comparison with other paratactic constructions shows that this derivative is a result of the historical substantivization of Slavic nouns used primarily in the attributive function. In place of its commonly accepted participial interpretation, the author treats the form Slovuta as an athematic denominative from PU *slov-ǫt-a continuing an earlier formation with the original meaning ‛the one who possesses the quality of *slov-’. The postulated base *slov- is characterized by onomatopoetic syncretism of both the sound of rinsing, washing, flowing (PIE *k̂leṷH-) and its perception (PIE *k̂leṷ-), while the termination -ā functions as a «noun class marker» designating a natural stream of fresh water. The author also argues that the underlying formation PIE *k̂leṷH-/ *k̂leṷ-ont-ā >*k̂leṷ(H)-ont-ā (> PS slov-ont-ā > PU slov-ǫt-ā > OU slov-ut-a) could have appeared in the early-inflecting «Old European» period in the formation of Indo-European, transitional from the active grammar type to the system of nominative-accusative grammar.