IPA: /rɪˈpleɪsər/
KK: /rɪˈpleɪsər/
A person or thing that takes the place of another.
The new employee is a replacer for the one who left the company.
Replacer → It is formed from "re-" (meaning again) and "place" (from Old French *placer*, meaning to put or set). The word "replacer" means to put something back again or to set it in its original position.
Think of putting something back 'again' ('re-') in its 'place' — that's why replacer means someone or something that puts things back.