כִּ֭י יִתְחַמֵּ֣ץ לְבָבִ֑י וְ֝כִלְיוֹתַ֗י אֶשְׁתּוֹנָֽן׃
Denn es war mein Herz erbittert, und in meinen Nieren fühlt ich es stechen.
Rashi on Psalms
For my heart was in ferment Before I saw this downfall with the holy spirit, my heart was in ferment because the way of the wicked prospered, and my mind was on edge (אשתונן), an expression of a sharpened sword (שנון). When it is reflexive, the “tav” is placed in the middle of the radical, as is the case of every word whose radical commences with “shin.”