This is the 15268th most frequent German word.
unerfüllbar
Impossible to fulfill.
Used to describe something that is impossible to achieve.
Es ist unerfüllbar, alle Sterne am Himmel zu zählen.
It is unattainable to count all the stars in the sky.
Used to express a wish or desire that cannot be realized.
Sein unerfüllbarer Wunsch war, nochmal die Vergangenheit zu ändern.
His unattainable wish was to change the past once more.
Applied to describe a task or goal that cannot be accomplished.