An Etymological Dictionary of the German Language/Glück
Glück, n., ‘luck, fortune, success, happiness,’ from MidHG. gelücke (by syncope glücke), n., ‘luck, accident’; OHG. *gilucchi is wanting; a specifically G. word which in the 14th cent. passed in the form into Scand. (Swed. lycka, Dan. lykke), and as luck into E. (from Du. geluk, ‘fortune’). On account of its meaning its connection with locken is dubious.