An Etymological Dictionary of the German Language/Annotated/klabastern

by Friedrich Kluge

klabastern, verb, ‘to run noisily,’ Modern High German only; originally a Low German term; in consequence of the entire absence of the word in the earlier periods of the languages its origin is dubious; it is most probably akin to Old High German klaphôn, Middle High German klaffen, ‘to clatter’; Anglo-Saxon clappian, English to clap.