suveren

1. (of a state, power) sovereign; independent
   Srbija je suverena i nezavisna država. — Serbia is a sovereign and independent state.
2. (of a performance, win) commanding; masterful
   Tim je ostvario suverenu pobedu nad rivalom. — The team won a commanding victory over its rival.

3. sovereign; ruler
   Kralj je bio suveren cele zemlje. — The king was the sovereign of the whole country.

The adverb suvereno means "confidently, in full control": suvereno vlada terenom.