oštećivati

1. to damage
   Deca stalno oštećuju klupe u parku. — Kids keep damaging the benches in the park.
   Pušenje polako oštećuje pluća. — Smoking slowly damages the lungs.
2. (financially) to cause losses to; to defraud
   Takvi ugovori godinama oštećuju državni budžet. — Contracts like these have been costing the state budget for years.

The perfective is oštetiti.