Dulling of the Heart (Dulling of the Senses, Dulling of the Mind)
Hardness of heart and loss of feeling. An inability to perceive through the senses. Figuratively: insensitivity to the feelings of others.
("It is narrated by Rabbi Yishmael: A transgression that stuns a person's heart, as it is said (and it was said, "And you shall not defile yourselves with them, and you shall be defiled by them; do not call upon them, and you shall be defiled, but you shall be stupefied" - Yoma 33a)
Translation
Expression (Hebrew)
טִמְטוּם הַלֵּב (טִמְטוּם הַחוּשִׁים, טִמְטוּם הַמּוֹחַ)
Definition (Hebrew)
קְשִׁיחוּת הַלֵּב וְאִיבּוּד הָרֶגֶשׁ. חֹוסֶר יְכֹולֶת לִקְלֹוט בַּחוּשִׁים. בְּהַשְׁאָלָה: אֲטִימוּת לְרִגְשׁוֹת הַזּוּלָת.
("תָּנָא דְּבֵי רַבִּי יִשְׁמָעֵאל: עֲבֵרָה מְטַמְטֶמֶת לִבּוֹ שֶׁל אָדָם, שֶׁנֶּאֱמַר (וַיִּקְרָא יָא) וְלֹא תִטַּמְּאוּ בָּהֶם וְנִטְמֵתֶם בָּם אַל תִּקְרֵי וְנִטְמֵאתֶם אֶלָּא וְנִטַּמְטֵם"- יוֹמָא לט ע"א)