What is feeling deprived or sad because of something another person has?

The term you are referring to is "envy". Envy is a negative emotion that arises when someone desires something that another person has, and resents that person for having it. It is a common human experience that can be triggered by a variety of things, such as material possessions, social status, romantic relationships, or personal qualities. Envy can be a powerful emotion that can lead to feelings of jealousy, bitterness, and resentment, and can even drive individuals to engage in negative behaviors in an attempt to obtain the desired object or outcome.