"Sheer incompetence" means a complete lack of ability or skill to do something correctly. It suggests that the person's performance or actions are extremely poor and unacceptable.
Sentences with «sheer incompetence»
It's actually huge act of sheer incompetence starting the season without enough signings. (justarsenal.com)
After that point, questions of funding become relevant only if it could demonstrated that their conclusions were scripted in the boardrooms of the fossil fuel industry, and not resulting from the skeptic scientists» sheer incompetence with understanding climate science. (gelbspanfiles.com)