np-

Np \Np\ n.
   The chemical symbol for Neptunium, a transuranic element
   having atomic number 93.

   Syn: Neptunium, atomic number 93.
        [WordNet 1.5]
    

NP-
 /N.P/, pref.

   Extremely. Used to modify adjectives describing a level or quality of
   difficulty; the connotation is often `more so than it should be'. This
   is generalized from the computer-science terms NP-hard and
   NP-complete; NP-complete problems all seem to be very hard, but so far
   no one has found a proof that they are. NP is the set of
   Nondeterministic-Polynomial problems, those that can be completed by a
   nondeterministic Turing machine in an amount of time that is a
   polynomial function of the size of the input; a solution for one
   NP-complete problem would solve all the others. "Coding a BitBlt
   implementation to perform correctly in every case is NP-annoying."

   Note, however, that strictly speaking this usage is misleading; there
   are plenty of easy problems in class NP. NP-complete problems are hard
   not because they are in class NP, but because they are the hardest
   problems in class NP.
    

NP
       No Problem (telecommunication, Usenet, IRC)
       
    

NP
       Network Performance