scarfpin (noun)

1. In the Sherlock Holmes series, the detective always wore a scarfpin to keep his tie perfectly in place.

2. As his disguise, the superhero always wore a scarfpin which concealed a hidden microphone.

3. The royal magician wore a scarfpin adorned with an enchanted gemstone that granted him special powers.

4. The fashion-forward gentleman added a touch of elegance to his outfit by wearing a scarfpin with a diamond accent.