This is a geminate root: its last two letters are the same (פ־ף), so the third radical doubles instead of appearing twice. One idea runs through the whole family: bending. From the bent hollow of a hand or spoon (כַּף), to a curved cap (כִּפָּה), to what is flexible (כָּפִיף) or hunched (כָּפוּף), to a person bent under authority, a subordinate. Even "to compel" comes from bending someone to your will. None of these are memorized separately. They are the same letters seen from different angles. Every word here is verified against pealim, niqqud included.
The same root runs through the verb system. Each binyan is a voice: it bends the one idea into active, passive, causative or reciprocal. Tap to hear.
Only the pa'al is lexicalized here, and it already carries both senses: the physical (to bend) and the figurative (to compel, to bend someone to your will). Because the root is geminate (פ־ף doubled), the infinitive contracts to לָכֹף rather than showing three separate consonants. The other binyanim stay empty for this root.
Same root letters, different noun moulds (mishkalim). The mould tells you the function: who does it, the act of doing it, or the thing produced.
Strip the prefixes, suffixes and vowels. Three consonants remain, and the meaning lives there.