An Etymological Dictionary of the German Language/Annotated/Koller
Koller (1.), neuter and masculine, ‘lady's ruff,’ from Middle High German koller, kollier, gollier, goller, masculine, ‘neckcloth,’ derived from French collier (Latin collarium).
Koller, (2.), masculine, ‘staggers,’ from Middle High German kolre, masculine, ‘staggers, frenzy, silent rage,’ Old High German cholero, masculine; derived, like a number of medical terms, mediately from Greek χολέρα, Latin cholera; the ch has also in Romance the value of a k; compare Italian collera, French colère.