Smelnif is not a widely know word, but anyone that knows the word will know exactly what it means, as the definition will have been told to them by a 'Smelnif guru'.
This word is deeply offencive, to the degree that if mentioned infront of a fellow follower or Smelnif, then they will probably call you Mr. Smelnif in a vulgar tone.
The most common time for Smelnif to be used is when somebody is being reffered to as Mr. Smelnif
"I hate you... MR SMELNIF!"
"Oh my god! Youre a right Smelnif you are!"