inoh

couldn't pour water out of a boot with the instructions on the heel

/ˈkʊd.n̩t po(ː)ɹ ˈwɔ.təɹ ɵut ʌv eː buːt wʰɪθ ðə ɪnˈstɹʌkʃənz ɔn ðə hil/

extremely incompetent or inept

“He couldn't pour water out of a boot with the instructions on the heel.”