When someone is a conplete noob at life, in a really cute/badass way. A knob is not necessarily a bad thing to be called. In fact, people are often very fond of knobs.
Dude 1: Haha, my cousin slipped on a banana peel. I didn't even know that was possible
Dude 2: What a knob!
Plug-ugly geezer who is also being a total git
What an Airy-Fairy Knob that Prat Joey is...
A man or woman who preforms fellatio in a frequent manner and indiscriminate manner.
Did you see Jessica all over David and Mark last night, she's such a knob stacker.
When your mother is constantly pissing you off about your cat being on the counter tops so you rub the cats ass all over the counter tops every handle and door knob in the house.
Dylan "I will rub the cats ass on everything"
I'm doing to stinky door knob the fuck out of this kitchen.