samostalan

1. (of a person) independent; self-reliant
   Naša ćerka je vrlo samostalna za svoje godine. — Our daughter is very independent for her age.
2. (of a state, organization) independent; autonomous
   Srbija je postala samostalna država 2006. godine. — Serbia became an independent state in 2006.
3. (of work, an exhibition) individual; solo
   Slikarka otvara svoju prvu samostalnu izložbu. — The painter is opening her first solo exhibition.
   Za ovaj posao je potreban samostalan rad. — This job requires working independently.

The adverb samostalno is common in phrases like živeti samostalno "to live on one's own".