An Etymological Dictionary of the German Language/Annotated/Karfreitag
Karfreitag, masculine, ‘Good Friday,’ from the equivalent Middle High German karvrîtac, mostly kartac, masculine; Karwoche, ‘Passion Week,’ is also current even in Middle High German. The first part of the compound is Old High German chara, feminine, ‘lamentation. mourning’ (charasang, ‘elegy’). This Old Teutonic word for Klage, ‘lament,’ as distinguished from the other synonyms, signifies properly the silent, inward mourning, not the loud wailing, for in Gothic the cognate kara, feminine, means ‘care,’ Anglo-Saxon cearu, feminine, ‘care, suffering, grief,’ English care. A corresponding verb signifying ‘to sigh’ is preserved in Old High German quëran (Gothic *qaíran). Other derivatives of the Teutonic root kar, qer, are wanting. See also karg.