An Etymological Dictionary of the German Language/halt
halt, adv., ‘moreover, forsooth, methinks,’ prop. a compar. meaning ‘rather,’ MidHG. and OHG. halt, adv., OSax. hald, ‘rather’; orig. a compar. adv. of the posit. adv. halto, ‘very.’ The compar. ending, according to the law of apocope, has disappeared, as in baß for the earlier batiz; orig. haldiz formed, like Goth. haldis, OIc. heldr, ‘rather.’ In no case is it related to the OHG. adj. hald, ‘inclined,’ mentioned under Halde; with the exception of the OHG. halto, adv., no other word in the posit. can be found.