An Etymological Dictionary of the German Language/Zunft
Zunft, f., ‘guild, corporation, club, sect,’ from MidHG. zunft, zumft, OHG. zumft, f., ‘propriety, rule, law; society governed by certain rules, union, association,’ guild’; allied to ziemen. OHG. zumft is derived from zëman, ‘to be proper,’ by means of the -ti (Goth. -þi), which forms verbal abstracts; for the intrusion of an f in the combination mt, comp. Kunft, Nunft, and Ramft. Hence the orig. meaning of Zunft is ‘suitability, propriety, that which is becoming or according to law.’ For the development of meaning comp. Gilde, derived from LG.