1 Pagum-Rashi explains that this means the daughter of a non-Jewish man and a Jewish lady is not allowed to marry a Kohen. The Ramban however says that the son produced from the aforementioned union is a Chalal (see below). According to the Ramban a Pagum is a Chalal.

2 Mekulkal-same as Pagum.

3 Chalal- a son of a Kohen who is born from a lady who is Pasul to marry a Kohen. The Chalal is not considered a Kohen, and therefore may not serve in the Beis ha'Mikdash or eat Terumah.

4 Shtuki-a child of a Jewish woman where the identity of the father is unknown. A Shtuki is considered a Safek Mamzeer, and even thogh Mi n ha'Torah he may marry either a Mamzer or a Yisrael, mi'Drabanan he may only marry a Ger.

Dov Freedman