Where does “decabrist” come from?

decabrist (Romanian) comes from Russian декабри́ст, from Russian дека́брь, from Latin december, from Latin decem, from Latin -nus, from Proto-Italic -nos, from Proto-Indo-European -nós — Creates verbal adjectives from roots.

decabrist (Romanian): Decemberist

Definitions

Decemberist

Ancestry of “decabrist”, step by step

Step	Language	Word	Meaning
1	Russian	декабри́ст	Decembrist (sympathizer of the Decembrist revolt)
2	Russian	дека́брь	December
3	Latin	december	of December; December
4	Latin	decem	ten; 10
5	Latin	-nus	-an
6	Proto-Italic	-nos	Creates verbal adjectives from verb stems
7	Proto-Indo-European	-nós	Creates verbal adjectives from roots

Every word from Proto-Indo-European -nós →Every word from Latin -nus →Every word from Latin decem →