Where does “Dekabristin” come from?

Dekabristin (German) comes from German Dekabrist, 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.

Ancestry of “Dekabristin”, step by step

StepLanguageWordMeaning
1GermanDekabristDecembrist
2Russianдекабри́стDecembrist (sympathizer of the Decembrist revolt)
3Russianдека́брьDecember
4Latindecemberof December; December
5Latindecemten; 10
6Latin-nus-an
7Proto-Italic-nosCreates verbal adjectives from verb stems
8Proto-Indo-European-nósCreates verbal adjectives from roots
Every word from Proto-Indo-European -nósEvery word from Latin -nusEvery word from Latin decem