IPA: /ˈwɔːkər/
KK: /ˈwɔkɚ/
A person or thing that walks, often used to refer to someone participating in a race or an individual using a device to assist with walking.
The walker finished the race in record time, impressing everyone with their speed.
Walker → It is formed from "walk" (from Old English *wealcan*, meaning to move by foot) and "-er" (meaning a person who). A walker is a person who moves by foot.
Think of someone who 'moves by foot' — that's what a walker does.