An Etymological Dictionary of the German Language/abtrünnig

by Friedrich Kluge

abtrünnig, adj., from the equiv. MidHG. abetrünncc (abetrünne), OHG. abatrunnîg, adj., ‘recreant’; orig. sense, ‘he who separates himself from,’ for trennen contains the same stem. Comp. also OHG. anttrunno, ‘fugitive,’ MidHG. trünne, ‘a detached troop.’