This root starts with decay: clothes fray, things grow old and fall apart. Then Hebrew makes a beautiful move. The pi'el takes the same idea of using something up and turns it onto time, you 'spend' your evening, you 'wear out' the hours, and the result is leisure, having a good time. So the same three letters give you both the threadbare coat and the great night out. Every word 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 in voice: the pa'al and hitpa'el keep the decay sense (something wears out on its own), while the pi'el takes the active twist toward 'spending time' and 'having fun'. One root, two moods, just by changing the binyan. No causative hif'il or passive pu'al is lexicalized here.
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.