cracker
     n 1: a thin crisp wafer made or flour and water with or without
          leavening and shortening; unsweetened or semisweet
     2: a poor white person in the southern United States [syn: {redneck}]
     3: a programmer who `cracks' (gains unauthorized access to)
        computers, typically to do malicious things; "crackers are
        often mistakenly called hackers"
     4: firework consisting of a small explosive charge and fuse in
        a heavy paper casing [syn: {firecracker}, {banger}]
     5: a party favor consisting of a paper roll (usually containing
        candy or a small favor) that pops when pulled at both ends
        [syn: {snapper}, {cracker bonbon}]
Source: WordNet® 2.0

cracker n. One who breaks security on a system. Coined ca. 1985 by
   hackers in defense against journalistic misuse of {hacker} (q.v., sense
   8). An earlier attempt to establish `worm' in this sense around 1981-82
   on Usenet was largely a failure.

   Use of both these neologisms reflects a strong revulsion against the
   theft and vandalism perpetrated by cracking rings. The neologism
   "cracker" in this sense may have been influenced not so much by the term
   "safe-cracker" as by the non-jargon term "cracker", which in Middle
   English meant an obnoxious person (e.g., "What cracker is this same that
   deafs our ears / With this abundance of superfluous breath?" -
   Shakespeare's King John, Act II, Scene I) and in modern colloquial
   American English survives as a barely gentler synonym for "white trash".

   While it is expected that any real hacker will have done some playful
   cracking and knows many of the basic techniques, anyone past {larval
   stage} is expected to have outgrown the desire to do so except for
   immediate, benign, practical reasons (for example, if it's necessary to
   get around some security in order to get some work done).

   Thus, there is far less overlap between hackerdom and crackerdom than
   the {mundane} reader misled by sensationalistic journalism might expect.
   Crackers tend to gather in small, tight-knit, very secretive groups that
   have little overlap with the huge, open poly-culture this lexicon
   describes; though crackers often like to describe _themselves_ as
   hackers, most true hackers consider them a separate and lower form of
   life.

   Ethical considerations aside, hackers figure that anyone who can't
   imagine a more interesting way to play with their computers than
   breaking into someone else's has to be pretty {losing}. Some other
   reasons crackers are looked down on are discussed in the entries on
   {cracking} and {phreaking}. See also {samurai}, {dark-side hacker}, and
   {hacker ethic}. For a portrait of the typical teenage cracker, see
   {warez d00dz}.


Source: The Jargon File