An incompetent person is often referred to as a DUFFER, which is a six-letter word. A DUFFER is someone who is not very skilled or knowledgeable in a particular area, and may be considered clumsy or inept. They may lack the necessary skills or experience to do a job properly, or may simply lack the motivation to do it well. Incompetent people may also be seen as lazy or irresponsible, and may not take responsibility for their mistakes.