An Etymological Dictionary of the German Language/Annotated/niesen

by Friedrich Kluge

niesen, verb, ‘to sneeze,’ from the equivalent Middle High German niesen, Old High German niosan, strong verb; corresponding to Dutch niezen, Old Icelandic hnjósa (to which hnore, masculine, ‘sneezing,’ is allied), Middle English nêsin; also Anglo-Saxon fneôsan, Middle English fnêsen, equivalent to Dutch fniezen, ‘to sneeze.’ The two Teutonic roots hnus and fnus seem to have been originally identical; with these are connected Middle English snêsen, English to sneeze. The pre-Teutonic root qnus, ksnus, may be onomatopoetic.