IPA: /ˈtʃɜːrtʃˌɡoʊər/
KK: /ˈtʃɜːrtʃˌɡoʊər/
A person who regularly goes to church services.
Every Sunday, the churchgoer attends the morning service with their family.
Churchgoer is formed from "church" (from Old English *cirice*, meaning a place of worship) and "goer" (from the verb "go", meaning to move or travel). A churchgoer is someone who travels to a place of worship, specifically a church.
Think of someone who 'travels' ('goer') to a 'place of worship' ('church') — that's what a churchgoer means.