smell: [12] Smell is something of a mystery word. It is assumed to go back to an Old English *smiellan or *smyllan, but no such verb has been recorded, nor have any related forms in other languages been pin-pointed for certain. One theory links it with English smoulder [14] and the related Dutch smeulen ‘smoulder’, as if the notion of ‘smelling’ arose from the idea of breathing vapour or smoke through the nose. [smell etymology, smell origin, 英语词源]