not know your ass from your elbow
US /nɑt noʊ jʊər æs frəm jʊər ˈɛl.boʊ/
UK /nɑt noʊ jʊər æs frəm jʊər ˈɛl.boʊ/
1.
nicht wissen, wo oben und unten ist, keine Ahnung haben
to be very stupid or ignorant; to lack basic knowledge or common sense
:
•
He's so incompetent, he doesn't know his ass from his elbow.
Er ist so inkompetent, er weiß nicht, wo oben und unten ist.
•
Don't ask him for help; he doesn't know his ass from his elbow when it comes to computers.
Frag ihn nicht um Hilfe; er hat keine Ahnung, wenn es um Computer geht.