תְּשִׁישׁוּת, (preced.) feebleness, frailty. Koh. R. to X, 17 (ref. to בשתי, ib.) בגבורתו ולא בתְשִׁישׁוּתוֹ (some ed. בתְשִׁישׁוֹ) (who does good) while he is in his strength, and not when he is feeble (old).