Flatfoot (noun)

1. A police officer, especially one who walks a beat.
2. A person with flat feet.

Origin:

Early 20th century: flat + foot.

Examples:

1. The old flatfoot had been on the beat for over thirty years.
2. The flatfoot was well known and respected in the neighborhood.
3. The young man was a flatfoot and proud of it.
4. She had been a flatfoot for ten years before making detective.
5. The flatfoot's feet ached after a long shift walking the beat.