An Etymological Dictionary of the German Language/Wahn

by Friedrich Kluge

Wahn, m. ‘illusion, delusion,’ from MidHG. and OHG. wân, m., ‘uncertain, unfounded opinion, supposition, belief, hoping, thoughts.’ The word (comp. Argwohn) did not originally contain the secondary meaning ‘want of foundation,’ as is shown by OSax. wân, AS. wên, Goth. wêns, ‘expectation, hope.’ Hence the derivative wähnen, ‘to think, believe, suppose,’ MidHG. wœnen, OHG. wânnen (from *wânjan), ‘to mean, suppose, hope,’ comp. the equiv. Goth. wênjan, AS. wênan, OSax. wânian. The nominal stem wêni is not related to any terms in non-Teut. (Aryan root wê?, ghwê, ghê?), unless it be connected with the root wen, ‘to love,’ from which OHG. and OSax. wini, ‘friend,’ Sans. van, ‘to love,’ and Lat. venerari, ‘to venerate,’ are derived.