DEUT61 The fifth category [of lashon hara is] -- obscene speech. Our Sages, z"l, said (Shabbos 33a), "One who speaks obscenities, even if a decree of seventy good years has been decreed upon him, it is transformed into evil." Yeshayahu also said (Yeshayahu 9:16), "Therefore, Hashem will unhappily [punish] their young men, and He will not pity [even] their orphans and widows, for they are all flatterers and wicked, and every mouth utters obscenities.. Yet, His anger has not subsided and His hand is still outstretched." [I.e., Yet, they still do not repent. Therefore, Hashem's anger remains and His hand is outstretched to punish even more (Radak)]. The reason one who speaks obscenities is heavy with sin [Yeshayahu 1:4] and loathsome and detested [Iyov 15:16] is because he has forsaken and deserted the [qualities of] shame and modesty, which are the recognized features of the holy seed [of Yisrael], and [instead] has gone along the pathway of insolence, which is the characteristic found in evil speakers of obscenity. The second [reason] [I.e., Why speaking obscenities is so sinful and odious] --For he has desecrated the holiness of Israel. [This is] because the pasuk states [this verse], "They will say, 'This great nation is purely a wise and intelligent people'"; yet he has conducted himself in the manner of detestable fools, removed from the path of intelligence [Mishlei 21:16] which is our beauty and pleasantness. Their foulness rises and their stench ascends [Yoel 2:20] and every wise, intelligent person will absolutely loathe them and utterly abhor them [Devarim 7:26]. He has desecrated the vessel of intelligence which is more precious than all [other] desirable vessels, as the pasuk says (Mishlei 20:15), "But the lips of knowledge are a precious vessel." [Thus, speaking obscenities entails two evils: (one) a lack of shame and modesty; (two) a desecration of the superior intelligence manifest in the Jewish people when they follow the way of Hashem.] One who listens to obscene speech is [also] very severely punished, for he has not sealed his ear or disassociated himself from those who speak obscenities. Regarding such a person the pasuk says (ibid., 22:14), "The estranged mouth is a deep pit; those despised by Hashem will fall there."