ثقّفهُ
1.
, (S, Msb, K,) verbal noun تَثْقِيفٌ, (S, Mgh, K, KL,) He straightened it, or made it even, (S, Mgh, K, KL,) or straightened what was crooked thereof; (Msb;) namely, a spear, (S, KL,) [and a bow, (see ثِقَافٌ,)] or a crooked thing; with the
ثِقَاف: (Mgh:) [and so
ثَقَفَهُ, according to an explanation of the verbal noun ثَقْفٌ in the KL.] تَثْقِيفُ
السَّهْمِ عَلَى القَوْسِ, as meaning The directing the arrow upon the bow straightly towards the object aimed at, is not approved. (Mgh.)
2.
Hence, (Mgh,) (tropical:) He disciplined him, or educated him well, and amended him, or improved him. (Mgh, TA.) You say, لَوْلَا تَثْقِيفُكَ وَتَوْقِيفُكَ مَا كُنْتُ شَيْيءًا (tropical:) [But for thy disciplining, or good educating, and amending, or improving, and thy teaching, I had not been anything]. (TA.)
3.
You say also, of vinegar, يُثَقِّفُ الطَّعَامَ, i. e. It makes food acid. (Har p. 227.)