This article proposes a new etymology in the lexical field that Wartburg relegated to various different parts of the volumes of Étymons inconnus, unaware of their unity. Having recovered all the available attestations of the lexeme naier ‘to solder, stitch together' and its derivatives, we investigate and discuss all the etymological and lexicographical proposals of the past few decades. Thanks to identification of the diffusion paths on the diatopic and diachronic axes, we wish to propose a new Old Dutch etymon *nājan for inclusion among the germanisms in FEW