mar

1. formal diligence; care; zeal
   Uredio je baštu s mnogo mara. — He laid out the garden with great care.
2. dated (nije koga mar) someone doesn't care
   Nije ga mar šta drugi misle. — He doesn't care what others think.
   Nikoga nije bilo mar za staru kuću. — Nobody cared about the old house.

A rare word; it occurs in the dated expression nije me (ga, ih…) mar, "I (he, they…) don't care". In modern speech people usually say nije me briga or ne marim.