Gemara

52a (Beraisa - R. Meir): "Es Aviha Hi Mechaleles" teaches that we no longer treat the father (of a gorl who was Mezanah) honorably (like other Kohanim). We say 'cursed is the one who fathered and raised such a girl.

(Rav Ashi): Even if a Rasha's father is a Tzadik, we call him a Rasha ben Rasha. This is like R. Meir.

103b (Beraisa - R. Meir): Avshalom has no share in the world to come. "Va'Yaku Es Avshalom" in this world. "Va'Ymisuhu" in the world to come.

Yoma 38b: Regarding Ben Kamtzar and his colleagues it says "v'Shem Resha'im Yirkav".

(R. Elazar): This teaches that we do not name people after them.

Eruvin 53a (Rav or Shmuel): The real name of Amrafel is Nimrod. He is called Amrafel because Omar v'Hipil (he commanded and threw) Avraham into a lit furnace (for refusing to serve idolatry);

(The other of Rav and Shmuel): His name is Amrafel. He is called Nimrod because he Himrid (made rebel against Hash-m) the entire world.

Bereishis Rabah (49:1) - R. Yitzchak: If one mentions a Rasha without cursing him he transgresses an Aseh - "v'Shem Resha'im Yirkav";

R. Shmuel bar Nachman says, names of Resha'im are like Kelim used for weaving. They are strong while used, but they slacken after use. Similarly, we do not hear people call their children Paro or Sisera or Sancheriv (their names die out).

On Purim, when Rav mentioned Haman he would say 'cursed is Haman and cursed are his sons', to fulfill "v'Shem Resha'im Yirkav".

Sotah 10b - Question: "My son Avshalom, my son, my son, Avshalom, if only I had died in your place..." Why did David say "my son" eight times?

Answer: Seven times were to save him from the seven chambers of Gehinom. Some say that the eighth was to get his head to rejoin his body. Others say, it was to bring him to the world to come.

(R. Chanina bar Papa): "The monument in Emek (valley) of the king" refers to the deep (Amukah) plan of the King of the world - "I will raise evil against you (David) from your house."

Rishonim

Tosfos (Yoma 38b DH d'Lo): R. Tam says that in Kesuvos 104b, the name of the judge must be Chanan ben Avishalom. It cannot be Avshalom, for R. Meir holds that Avshalom has no share in the world to come, and we do not give a child a Rasha's name. The name Avishalom is in Melachim (1:15:2).

Rashi (Yoma 38b DH d'Lo): One should not give to his son the name of a Rasha.

R. Chananel (Yoma 38b DH she'Ein Adam): Someone given such a name will not succeed.

Tosfos (Yoma 38b DH d'Lo): One may give a name if it was in the name of a Tzadik and of a Rasha. R. Tam says that in Kesuvos 104b, the name of the judge must be Chanan ben Avishalom (not Avshalom), for R. Meir holds that Avshalom has no share in the world to come. Similarly, in Shabbos (12b) the text must say Shechna, for Shevna was a Rasha. Some say that there were two Shevnas, and one (Shevna ha'Sofer) was a Tzadik, therefore, we may call people by this name. Really, they are one person. The Torah (Navi) is out of order.

Rashi (Mishlei 10:7): "V'Shem Resha'im Yirkav" - people will not want to give such names, therefore the name will rot.

Sefer Chasidim (790): If a Nochri helped Yisraelim, we may ask Hash-m to ease his judgment. The same applies to a Mumar who helped Yisre'elim. We remember Charbano for the good, for he spoke against Haman. David prayed to save Avshalom from Gehinom because David's sin caused Avshalom to sin. It will not help for a convert to pray to ease the judgment of his parents. If a Tzadik's parents caused many to sin, he should not seek to help their Neshamah, for it says v'Shem Resha'im Yirkav.

Sefer Chasidim (938): If someone gave a nice reason in Torah, a then became an idolater, we do not say it in his name. If one says it in his name, we do not add 'Zichrono li'Vrachah' nor v'Shem Resha'im Yirkav. One should not benefit from a Rasha. Sometimes a Tzadik benefits from a Rasha, and he loses it, in order that he not benefit from a Rasha.

Poskim

Shulchan Aruch (OC 690:17): The custom is for children to wrap the image of Haman on sticks and stones, or to write his name on them and bang them together, in order to wipe out his name - "Timcheh Es Zecher Amalek", "v'Shem Resha'im Yirkav". From this came the custom to bang when Haman's name is read.

Beis Yosef (DH Kasuv b'Orchos): There is a source in the Medrash - "Emcheh Es Zecher Amalek", even from sticks and stones.

Magen Avraham (21): The Levush says that when they say Haman, one says v'Shem Resha'im Yirkav.

Sha'ar ha'Tziyon (57): One should not say this. Even if it is not a Hefsek, because v'Shem Resha'im Yirkav is a theme of the day, perhaps he will miss a word from the Shali'ach Tzibur, and he was not Yotzei.

Mishnah Berurah (59): The Maharal did not bang on Haman's name. The Chacham Tzvi would stamp his foot. The Pri Megadim says that they lose more than they gain, for it greatly befuddles.

Kaf ha'Chayim (108): A support for the custom is "v'Hayah Im Bin Hakos ha'Rasha" - the last letters of the first three words spell Haman. Ru'ach Chayim (696) says that people say that every year when we bang, Haman is stricken in Gehinom.

Pischei Teshuvah (YD 116:6): Adnei Paz (25,34) says that if one died, his brother should not be given his name, for it has a bad Mazal. Surely, the same applies to a stranger who died (young). Perhaps the reason we do not call people by names of Resha'im is due to bad Mazal. However, Yoma 38b connotes otherwise.

Acharonim

Toras Chayim (Eruvin 53a DH v'Chad): If Amrafel was his real name, and Nimrod is merely a nickname, one may call his son Nimrod, but not Amrafel, and vice-versa if his real name was Nimrod.

Toras Chayim (Bava Basra 143b DH Rav): Rav Yosef provef that one son is called 'Bnei' from a verse after "u'Vnei Karmi Ochar Ocher Yisrael Asher Mo'al ba'Cherem", for one could say that Karmi had two sons, Ochar and Achan. The verse did not call him by his name, due to v'Shem Resha'im Yirkav.

Maharsha (Ta'anis 28a DH Hu Omer): It is forbidden to call someone by a Rasha's name.

Question: Why don't the Poskim bring this Isur?

Answer (Si'ach ha'Sadeh p. 44b) The Poskim hold that it is not an Isur. Rather, it is only Midas Chasidus. "V'Shem Resha'im Yirkav" is not a command. It is a curse, like we find in Bereishis Rabah (49:1).

Question: We find Tzadikim that used names of the Meraglim, i.e. Shamu'a and Shofat!

Answer (Pnei Yehoshua Kesuvos 104b DH Shnei Dayanei): We attribute their evil to the name 'Meraglim', and not to their individual names. Alternatively, it is forbidden only regarding a name that itself suggests evil, e.g. Do'eg (Hash-m 'worried' lest he become evil - Sanhedrin 96b). Perhaps regarding a typical name we may assume that there were Tzadikim of that name before the Rasha. However, Tosfos asked why a Tzadik was called Avshalom. This shows that he disagrees with the latter two answers.

Chasam Sofer (Parashas Korach DH Korach ben Yitzhar): It is difficult to understand why a righteous Levi called his son by in the name of a Rasha (Korach was a chief of Edom - Bereishis 36:16). Perhaps the verse traces his lineage to Levi to teach that in spite of three ancestors who were Tzadikim, his name helped cause him to be a Rasha.

Ziv ha'Shemos cites Acharonim who say that it is not forbidden to give the name of a Rasha, it is only Midas Chasidus. Mishneh Halachos (4:114) says that it is forbidden.