If a person Plays Fast And Loose they can’t be trusted, usually with another's affections. For centuries, “Fast and loose” was a popular gambling game played in fairgrounds and market places all over Europe. It was originally known as “pin and girdle” and was played with loops made of leather straps, which were tossed over pegs. The “fast” is used in the sense of a fixed object – the peg – and the “loose” was originally “loops” before it developed in the 15th century to become the expression we use today. Apparently, the game was played with “carefree abandon” and it is because of this that the phrase “fast and loose” came to being applied to carefree and shallow attitudes.