IPA: //ˈpiːsˌkiːpər//
KK: /ˈpisˌkipər/
A person or group that helps to maintain peace, especially in a conflict area, often as part of a military or international effort.
The peacekeeper worked tirelessly to ensure safety in the war-torn region.
Peacekeeper → It is formed from "peace" (from Old French *pais*, meaning tranquility or absence of war) and "keeper" (from Old English *cepan*, meaning to guard or protect). A peacekeeper is someone who guards or protects peace and tranquility.
Think of someone who 'guards' ('keeper') 'tranquility' ('peace') — that's why a peacekeeper is someone who protects peace.