One idea sits at the centre: void, null, brought to nothing. To cancel is to make a thing void; a person who comes to nothing, who does nothing, is an idler; the state of having no work is unemployment. The root swings between two faces, an active "to cancel" and a passive/reflexive "to be idle, to come to naught". From there it builds the noun for cancellation, the loafer, and the social term for unemployment. 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.
The pi'el levatel is the workhorse, "to cancel" something actively; the hitpa'el lehitbatel turns it inward, to be idle or come to nothing. The pa'al livtol is mostly literary. The passives pu'al and huf'al and the hif'il are not lexicalized here, which is why "to be cancelled" is carried by the pi'el/hitpa'el pair rather than a dedicated passive.
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.