someone who makes a lot of serious mistakes, usually because of not taking care

The chief constable is seen by some as a blunderer. 警察局长被一些人认为是一个轻率行事，易犯大错的祸头子。

We should be blaming the incompetent blunderers who got us into this mess in the first place. 我们应该归咎于那些能力差，轻率行事，一开始就把事情搞得一团糟的人。