The term "slippered pantaloons" comes from the fact that they were often worn with slippers, which were a type of low, soft shoe. This type of footwear was popular in the 18th century, as it was comfortable and did not require buckles or laces.
Slippered pantaloons were a versatile garment that could be dressed up or down. They were often worn with a long coat and waistcoat in public, but they could also be worn with a simple shirt or jacket at home. They were a popular choice for gentlemen of all ages, and they were often passed down from generation to generation.
Today, slippered pantaloons are still sometimes worn as a novelty item, but they are no longer in common use. They are a reminder of a more relaxed time, when people were more concerned with comfort than with fashion.