What is the meaning of "She'eiro"?
Rashi: "She'eiro" means 'his wife'. (Refer to 21:2:155:1.)
Targum Onkelos: With reference to the list of relatives that follows, it means 'his close relatives'.
Moshav Zekenim, citing Toras Kohanim: Also a sister is called She'er (your aunt is called She'er Avicha - 18:12) because they came from the same womb. Also here, it refers to his wife, because they are called "Besar Echad" (Bereishis 2:24),
Is a Kohen Metamei for a relative who was a Nefel (stillborn)?
Da'as Zekenim, Hadar Zekenim: He is Metamei for relatives like his father and mother, who were not Nefalim.
Here it mentions his mother before his father. Regarding a Kohen Gadol (verse 11), it mentions his father first!
Da'as Zekenim, Hadar Zekenim, Moshav Zekenim, Rosh: The bigger Chidush is taught last. 1 Even though it is not Vadai his father (perhaps his mother was Mezanah 2 ), he is Metamei. A Kohen Gadol is not Metamei even for his mother, even though she is Vadai his mother.
Moshav Zekenim: There is a Chidush in his mother. Even if she became disqualified through Bi'ah to a Pasul, he is Metamei for her.
If so, the son has no Isur Tum'ah (he is a Mamzer, and not a Kohen)! It is a Chidush is that we force him to be Metamei for him, even though he is not Vadai (Moshav Zekenim).
Do we distinguish between paternal and maternal siblings!
, Hadar Zekenim, Moshav Zekenim, Da'as Zekenim (citing Toras Kohanim): Yes! He is Metamei only for paternal siblings, who [potentially] could inherit him, similar to his son and daughter.
What do we learn from "ha'Karov Elav"?
Hadar Zekenim: This excludes other relatives, e.g. an uncle.
QUESTIONS ON RASHI
Rashi writes that "She'ero" means his wife. If so, it should be feminine ("ha'Kerovah", like the next verse)!
Sifsei Chachamim: She'er refers to She'er Basar, which is masculine.