White Hat - re hackers who work entirely within the law
they are also motivated to explore systems for intellectual curiosity, rather than for malicious or criminal intent. White hat hackers oppose doing damage to systems, stealing data, or interrupting service to a Web site. But their activities may be illegal if they explore systems they aren't authorized to enter. White hats can also unintentionally damage or delete data. Many white hat hackers work as well-paid security consultants, programmers, and network administrators.

Black Hat - is the other way around , they are malicious. Well hmm lets see If you think of www as the wild, wild west, then you can guess on which side of the law the black hat hacker operates. Black hat hackers (aka "crackers") steal data or damage systems. The most dangerous black hats are able to remain undetected for years, secretly monitoring a victim's PC for whatever nefarious purpose they have in mind

Grey Hat - is just in between white hat and black hat
Gray hat describes a cracker (or, if you prefer, hacker) who exploits a security weakness in a computer system or product in order to bring the weakness to the attention of the owners. Unlike a black hat, a gray hat acts without malicious intent. The goal of a gray hat is to improve system and network security. However, by publicizing a vulnerability, the gray hat may give other crackers the opportunity to exploit it. This differs from the white hat who alerts system owners and vendors of a vulnerability without actually exploiting it in public

IP spoofing, also known as IP address forgery or a host file hijack, is a hijacking technique in which a cracker masquerades as a trusted host to conceal his identity, spoof a Web site, hijack browsers, or gain access to a network. Here's how it works: The hijacker obtains the IP address of a legitimate host and alters packet headers so that the legitimate host appears to be the source.

DEADLOCK n. A situation wherein two or more processes are unable to proceed because each is waiting for another to do something.

Daisy Chaining - This is what every good hacker does to avoid getting caught. Basically, you gain entry to a computer or network and use it to gain access to another, then to another. Hackers who get away with database theft usually do this then backtrack (this means they go backward after doing what they intended nd cover their tracks by destroying logs etc).
script-kiddie - This term denotes those who do not know how to hack systems but use malicious code written by others to do their damage.

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