Definition & Meaning of "[play] fast and loose with {sb/sth}"

What is the origin of the idiom "play fast and loose with someone or something" and when to use it?

The origin of the idiom "play fast and loose with someone or something" can be traced back to medieval games of chance, particularly a game called "fast and loose" that was popular in the 16th century. In this game, a belt or cord was looped in intricate patterns, and participants were challenged to unravel it while betting money. The person running the game would manipulate the loops to make it seem easy to win, but it was designed to deceive and take people's money. It is used in various situations, such as discussions about trust, relationships, ethics, and responsibility.