Authigenic neodymium isotopes (ε_Nd) are widely used to reconstruct past ocean circulation, yet their interpretation in marginal basins remains uncertain because local lithogenic inputs may overprint water-mass signals. The Mediterranean Sea provides an ideal natural laboratory to evaluate these competing controls owing to strong particle supply and rapid overturning circulation. Here we present new foraminiferal ε_Nd records from two sediment cores in the Levantine Basin (818 and 1809 m water depth) spanning the last ~14 kyr. Both records display radiogenic values during sapropel S1, a pronounced unradiogenic excursion during the 8.2 ka event, and a progressive late-Holocene decline followed by renewed radiogenic shifts after ~2 ka. Comparable ε_Nd amplitudes at both depths, together with the absence of systematically more radiogenic values at the deeper site, argue against dominant benthic overprinting. Instead, the data support top-down redistribution of reactive Nile-derived Nd released within the upper to intermediate water column. Following sapropel termination, progressively less radiogenic ε_Nd values likely reflect reduced Blue Nile discharge and shifts in Nile sediment provenance associated with weakening African monsoon intensity. By contrast, the 8.2 ka excursion records rapid renewal by relatively unradiogenic Adriatic-derived deep waters, showing that abrupt overturning can temporarily override background source effects. The broad correspondence between Levantine ε_Nd and independent monsoon proxies further suggests that authigenic ε_Nd can provide a marine archive of North African hydroclimate. These results demonstrate that authigenic ε_Nd in the Levantine Basin was strongly state dependent: during stable conditions it primarily tracked external detrital forcing, whereas during abrupt ventilation events it recorded water-mass reorganization. Authigenic ε_Nd in river-influenced marginal seas should therefore be interpreted as a dynamic tracer of both continental forcing and ocean circulation.