This root holds a single hinge: telling apart what you know from what you don't. Tip it one way and you get recognition, knowing a face, getting acquainted, being aware. Tip it the other way and you get the stranger, the foreign, even alienation, pushing someone into the not-known. The same act of marking a difference becomes either acquaintance or estrangement. From it Hebrew even builds הַכָּרָה, the word for consciousness itself. Every word below 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.
Notice the split. The hif'il לְהַכִּיר is the everyday "to know someone", positive recognition. The pi'el לְנַכֵּר takes the very same letters and pushes the opposite way, to make foreign, to alienate. The nif'al is the passive: to be recognised. One root, recognition and estrangement back to back.
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.