IPA: /ˈɡeɪtˌkiːpər/
KK: /ˈɡeɪtˌkiːpər/
A person who controls access to a place or service, often deciding who can enter or use it.
The gatekeeper at the concert checked tickets before allowing people inside.
Gatekeeper → It is formed from "gate" (from Old English *geat*, meaning an opening or entrance) and "keeper" (from Old English *cepan*, meaning to guard or protect). A gatekeeper is someone who guards or controls access to an entrance or opening.
Think of a person who 'guards' ('keeper') an 'opening' ('gate') — that's why a gatekeeper controls who can enter.