aktivirati

1. to activate; to enable
   Morate da aktivirate nalog preko mejla. — You need to activate your account via email.
   Aktivirala sam novu karticu u banci. — I activated my new card at the bank.
2. (of a bomb, alarm) to set off; to detonate
   Neko je slučajno aktivirao alarm. — Someone accidentally set off the alarm.
   Bomba je aktivirana daljinski. — The bomb was detonated remotely.
3. (aktivirati se, of a device, process) to go off; to become active
   Alarm se aktivirao usred noći. — The alarm went off in the middle of the night.
   Vulkan se ponovo aktivirao. — The volcano has become active again.
4. (aktivirati se, of a person) to get involved; to become active
   Posle penzije se aktivirao u lokalnoj zajednici. — After retiring he got involved in the local community.
5. (of soldiers, players) to call up; to put back into active service
   Vojska je aktivirala rezerviste. — The army called up the reservists.

The word is shared by Serbian and Croatian; the reflexive aktivirati se means "to go off" or "to get involved".