כָּאֵב (b. h.) to be heavy, to feel pain. Y. Sabb. IX, 12ᵃ ib. XIX, 17ᵃ bot. (ref. to Gen. XXXIV, 25) בהיותו כּוֹאֵב כל איבריהם כּוֹאֲבִים עליהם … it does not say, ‘when it (the wound) was painful’, but …, which intimates that all their limbs pained them.
Hif. - הִכְאִיב to cause pain, grief. Ex. R. s. 3 (ref. to Ex. III, 7) ידעתי … להַכְאִיבֵנִי וכ׳ I know how much they will grieve me &c. Pirké d’R. El. ch. XII שלא להַכְאִיבוֹ so as to make him feel no pain. Midr. Till. to Ps. XCIV (ref. to Prov. III, 12) א"ת וּכְאָב אלא וּכְאֵב … שמַכְאִיבוֹ read not ukh’ab (and like a father) but ukh’eb (and pain), when He sends him pain.