"What does that mean?"
"It means hes the Fat Dumb Kid"
"Well it fits..."
Whilst FDK has a derogitive connotation and referenced in a slightly angered mannar, its intentional use is not to denigrate.
The appropriate context to apply FDK, is when the subject (i.e. the FDK) has no reason to be an FDK, but chooses to be an FDK, to spite his friends.
Also to note, FDK should only be used to describe males. The appropriate term for a female of a difficult nature is FFH. (click for a definition)
He's got plenty of doe to blow,
he likes drinkin up and pervin,
he's got nothing else better to do,
and yet when his friends call him out on a friday night to get pist and womenise, he declines! what an FDK
eg2. Henry.. YOU FUCKING DIFFICULT KUNT