farba

1. paint
   Pazi, farba na klupi još nije suva. — Careful, the paint on the bench isn't dry yet.
   Kupili smo belu farbu za dnevnu sobu. — We bought white paint for the living room.
2. (for hair, fabric) dye; hair dye
   Farba za kosu mi je isprljala peškir. — The hair dye stained my towel.
3. colloq. colour
   Koje je farbe tvoj novi auto? — What colour is your new car?

The word boja is more neutral and covers all these meanings.