In a good sense it means having a feeling of self-respect. People can be satisfied with their achievements. They can be proud of something good that they have done. They can be proud of (or "take pride in") their work. They might be proud of their son or daughter or husband or wife or anyone else who is close to them and who has done something good. People can be proud of their country (patriotism). The opposite would be "to be ashamed" of someone or something. 