1. A person who is completely clueless about how stupid they look and act.
2. A person who is an asshole and an idiot.
4. Some one who usually tries to screw people over but are too ignorant to accomplish it.
3. Related to the phrase "dumb as a door knob", except the person is also an asshole. They are a "fuck knob."

Synonyms: Dumbass, Moron, Idiot, Retard, Fucktard.
"My neighbor was caught on camera climbing my fence and urinating in my pool but denied it. What a fuck knob!!"
by Bob Andweave August 7, 2007
Another, less prurient, name for the male cock, penis, member, knob, rod, stiffy. Often referred to as an Engorged Fuck Knob when fully erect and rigid.
Kara loved to give head. She loved nothing more than to inhale her boyfriend's engorged Fuck Knob and suck him to completion.
by Eaton Holgoode April 28, 2015
An insult meaning pathetic or obnoxious person. Same as insults like "Dickhead".
"He's such a Fucking knob"
"Go kill yourself"(reply) "your such a fucking knob"
by Billy Mcgee August 10, 2011
A stupid person whose only purpose is to waste oxygen. (See also douche bag)
"Get the hell out of my way, you fuck-knob!"
by vicfan March 24, 2004