An Etymological Dictionary of the German Language/harsch
harsch, adj., ‘hard, rough,’ ModHG. simply; E. harsh (‘bitter, severe’); unknown to AS., OHG., and OIc. Clearly a derivative of hart; comp. rasch, allied to grade, Goth. *rasqa- to raþa-, ‘quick’ (OHG. rado), OIc. horskr, ‘quick,’ to AS. hrade, OIc. beiskr, ‘bitter,’ to Goth. bait-ra-; hence Goth. hardus, ‘hard,’ perhaps presupposes *harsks, *harsqs. Yet it might also be connected with Ic. hörtl, ‘hardness of the frozen ground’; ModHG. Harsch, ‘snow-crust,’ dial. But hart (‘hard’) alone suffices to elucidate this latter sense, as is shown by OHG. hęrtemânôt, MidHG. hęrtemânot, ‘hard month,’ applied to December and January. See the following word.