masivno

1. (of build, structure) massively; solidly; heavily
   Zgrada je masivno građena, sa debelim zidovima. — The building is solidly built, with thick walls.
   Njen brat je visok i masivno građen. — Her brother is tall and heavily built.
2. (of scale, extent) massively; on a huge scale
   Država masivno ulaže u nove puteve. — The state is investing massively in new roads.

Don't confuse with masovno 'en masse', though they overlap in the second sense.