IPA: /ˈdjuːəmvɪr/
KK: /ˈduːəmˌvɪr/
A person who is part of a group of two people sharing power or authority, especially in a political or official role.
The two duumvirs worked together to make important decisions for the city.
Duumvir is formed from "duo" (meaning two) and "vir" (meaning man). The term refers to a political office held by two men, typically in ancient Rome, who jointly exercised power.
Think of 'two' ('duo') men ('vir') working together in a shared role — that's what a duumvir is.
No commonly confused words.