Where does “ragazzume” come from?

ragazzume (Italian) comes from Italian -ume, from Latin -umen, from Latin -men, from Proto-Italic *-mn̥.

Ancestry of “ragazzume”, step by step

Step	Language	Word	Meaning
1	Italian	-ume	Used to form nouns, often derived from...
2	Latin	-umen	—
3	Latin	-men	forms neuter nouns of the third declension
4	Proto-Italic	*-mn̥	—