Off-

Chamber's Twientieth Century Dictionary · 1908 · p. 127

(A.S.), off, from, away, as of fal, off shoot, off set. [A form of Of . There is the same relation between of and off as between be and by ; A.S. of has been differentiated into the stre le or weak form of , and the stre ed or strong form off . Cf. A-, Ab-.]