This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
捁 combines 扌 (hand) with 告, but the exact historical development and original meaning are uncertain.
With a hand 扌 beside 告 (inform), imagine a hand making a gesture to inform or signal, but the exact meaning is unclear.
For カク, imagine a hand making a sharp, angular gesture: the sound 'kak' (like 'cut') cues カク.