חָמֵץ I (b. h.; v. preced.) [to be hot,] to ferment, be sour. Ad. Zar. 68ᵇ מי גרם לה שתֶּחְמַץ וכ׳ what was the cause that it (the dough) became leavened (rose) in one hour?
    Pi. - חִמֵּץ to cause leavening. Ib.ᵃ ראויה לחַמֵּץ וכ׳ Ms. M. (ed. לחַמֵּעַ) fit to leaven with it many other doughs. Ib. וחִימְּצוּ; Orl. II, 11 נצטרפו וחִמְּצוּ (Y. ed. הצטרפו וחִימֵּיצוּ) and the two combined produced the required leavening, Ib. 9 וחִמְּצָהּ (Y. ed. וחִימֵּיצָהּ; Ab. Zar. l. c. והֶחְמִיצָהּ) and it made the dough rise. Orl. II 6 כל המְחַמֵּץ whatever is used for producing fermentation; a. fr.—Trnsf. to mature, to continue a case over night, to reserve judgment. Snh. 35ᵃ (ref. to Is. I, 17, v. preced.) אשרו דיין שמְחַמֵּץ את וכ׳ Ms. K. (ed. אשרי, v. Rabb. D. S. a. l. note 20) praise the judge (in capital cases) who reserves his judgment (over night); Yalk. Is. 257.
    Hif. - הֶחְמִיץ 1) same. Pes. 40ᵃ מי פירות אינן מַחְמִיצִין juice of fruits produces no leavening (in the ritual sense). Ab. Zar. 68ᵃ כדי להחמיץ (Orl. II, 8 לחַמֵּץ) enough to leaven the dough. Mekh. Bo s. 10 שאור שהוא מַחְמִיץ לאחרים leaven which is used for leavening other doughs; a. fr.—Trnsf. to procrastinate. Ib. s. 9 (play on המַצּוֹת, Ex. XII, 17) כדרך … אין מַחְמִיצִין את המִצְוָה as well as you must not allow the matsah to become sour, so you must not allow the mitsvah (religious act) to become sour by postponement; Yalk. Ex. 201. —2) to turn sour, to ferment. Ab. Zar. 68ᵇ ראויה להַחְמִיץ וכ׳ (Ms. M. לחמע) is likely to ferment in two hours. Nidd. IX, 7 מי רגלים שהֶחְמִיצוּ urin which ferments.—Trnsf. to degenerate, become wicked. R. Hash. 3ᵇ קודם שה׳ before he (the Persian King) changed for the worse.
    Nithpa. - נִתְחַמֵּץ to become sour (חָמֵץ). Pes. 28ᵇ; 43ᵃ נ׳ מאליו became sour of itself (not through a leavening means).