An Etymological Dictionary of the German Language/Annotated/stolz
stolz, adjective, ‘proud, haughty, arrogant,’ from Middle High German, late Old High German stolz, ‘foolish, arrogant, stately, splendid, magnificent, high-minded.’ The assumption that the word was borrowed from Latin stultus, ‘foolish,’ whence Italian stolto, ‘foolish,’ does not meet the case, for Old French estout, ‘arrogant, bold,’ is borrowed from pre-High German *stolto-, the meaning of which is scarcely explicable by Latin stultus, only Middle High German stolz, ‘foolish,’ shows the influence of the Latin and Italian signification. Teutonic *stolto is considered to be cognate with Stelze. English stout seems to be borrowed from Middle Dutch stout (for stolt), with a different development in meaning. — Stolz, masculine, ‘pride,’ is a substantive lately formed from the adjective.