IPA: /ˈpɜːrfɛktər/
KK: /ˈpɜrˌfɛktər/
A person who makes something better or improves it to a high standard.
The perfecter of the recipe added a special ingredient to enhance the flavor.
Perfecter → It is formed from "perfect" (from Latin "perfectus", meaning completed or finished) and "-er" (meaning a person who). A perfecter is a person who makes something perfect or completes it.
Think of someone who makes something 'complete' or 'finished' — that's what a perfecter does.