An integer is any whole number, positive or negative, including zero. Whole numbers are the non-negative integers, which include 0 and all positive integers.
Let's analyze the options given:
- 0 is an integer and also a whole number.
- -2 is an integer but not a whole number.
- 7 is an integer and a whole number.
- 783 is an integer and a whole number.
Therefore, the integer that is not a whole number is -2.