An Etymological Dictionary of the German Language/seufzen
seufzen, vb., ‘to sigh, lament,’ from the equiv. MidHG. siufzen, siuften; the z of the MidHG. form is due to the influence of the intensives in -zen; in OHG. sûftôn, sûfteôn, ‘to sigh,’ allied to MidHG. sûft, ‘sigh.’ The latter is an abstract from OHG. sûfan, ‘to drink’; hence seufzen, lit. ‘drawing in the breath’; it is related to saufen, as schluchzen is to schlucken. Note, however, E. to sob, MidE. sobbin, AS. *sobbian, ‘to sob, sigh,’ which may be allied to OHG. sûfteôn.