Phising is trying to get someones username, password, credit card info, Social, or video mesum other personal information by means of a fraudulent message, email, instant message.
Hacking is refered to as getting into another system or computer and copying, modifying, or just looking a data on that host PC.
Cracking is actually chaning code, or modifying a program to function beyond its limits, delete registration, or any other modification of that program.
These are very basic ideas, and I only gave a few of MANY examples, but at least you have the idea now.