Select the most appropriate one-word substitution for the given group of words.

A person who gambles or bets 

Punter

The most appropriate one-word substitution for "a person who gambles or bets" is punter.

• Mentor is a trusted advisor or guide.
• Philanthropist is a person who donates money or time to charitable causes.
• Bohemian is a person who lives an unconventional or nonconformist lifestyle.

The word punter comes from the Old English word "punt," meaning "to thrust." A punter is a person who bets on sporting events or other uncertain outcomes. They are often seen as taking risks and living on the edge.