An Etymological Dictionary of the German Language/spähen
spähen, vb., ‘to spy,’ from the equiv. MidHG. spëhen, OHG. spëhôn. This word and the OHG. and OSax. adj. spâhi, MidHG. spœhe, ‘prudent, skilful’ (and Du. bespieden, ‘to spy’?), are the sole relics of the OTeut. root speh, ‘to see,’ which, through Lat. spec in speculum, conspicio, adspectus, as well as through Sans. spaç, ‘to see’ (Gr. σκέπ-τω for *σπέκτω?), is proved to be primit. Aryan (Aryan root spek). From the Teut. cognates those of Ital. spiare, Fr. épier, ‘to spy out’ (Ital. spione, Fr. espion, ‘spy,’ whence E. spy), were borrowed at an early period.