1. feeling sorry for the person;
2. if the person is cute, but in a dorky sort of way;
3. if something awkward happens to a person (dorky or not)that person and the whole situation will be nebish for the time being.
Nebish may also be used in some instances to replace the word shame, like: oh shame, that guy has his pants on backwards and everyone's laughing.
2. its so nebish (sad), every lunch time she sits and reads by herself.
3. haha did you see Matty trip when he got up on stage? nebish!