IPA: /ˈpɪərsər/
KK: /ˈpɪr.sɚ/
A person or tool that makes holes in something, often used for body piercing or to create openings.
The tattoo shop also has a professional piercer who can safely perform body piercings.
Piercer → It is formed from "pierce" (from Old French *percer*, meaning to penetrate or break through) and "-er" (meaning a person who). A piercer is a person who penetrates or makes a hole in something.
Think of someone who 'penetrates' ('pierce') something to create a hole — that's what a piercer does.