An Etymological Dictionary of the German Language/Annotated/helligen

by Friedrich Kluge

helligen, behelligen, verb, ‘to importunate,’ from Middle High German hęlligen, ‘to weary by pursuit, tease, torment’; a nominal verb from Middle High German hęllic, adjective, ‘wearied, exhausted,’ Modern High German hellig, ‘wearied.’ The origin of the adjective is obscure.