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1.
Nick and Jeff Warbler's (from Glee) fandom-made couple name.
Person on livestream: Do you ship Niff?
Nick: ...*huge smile*
by GeeUrie February 10, 2012
 
2.
Everything and anything and everything inbetween!
I'm just a stupid niff!" "I will niff you." "Get the niff outta hurr." "Niff you n-n-niff you!" "Written in the niffs!" "Niffy niffs!" "Stroke a niff." "Rollin like a big niff.." "MLIN" (MY LIFE IS NIFF
by Nifferologist! May 30, 2011
 
3.
boolean inverse of the function iff, equivalent to xor
same as nand or nor
0 niff 0 =0
1 niff 0 =1
0 niff 1 =1
1 niff 1 =0
by geek_1024 April 30, 2012
 
4.
Niff is a street name for poppers.
also used for sniffs,
pass me the niff mate

ive only had 3 niffs
by agatha chris June 15, 2009
 
5.
an abbreviation for niffler. its derived from the creature in harry potter which sniffs out gold, but it simply means "nothing" or "nevermind." see niffler
Dude 1: what's that your hiding under your bed, d3wd?
Dude 2: niff.
Dude 1: ok, if your sure.
Dude 2: just forget it, man.
by forearm October 17, 2005
 
6.
Nigga I frequently fuck
Jenni: Isn't that yo boyfriend

Eva: NO! He's just a NIFF
by Eva Ehrat September 15, 2011
 
7.
An English 50 pence piece. Hand in hand with biff
Mr D's sell large chips for a biff niff
by Will Satterthwaite May 30, 2005