The term DECREPIT HORSE is composed of two words, NAG (3 letters) and PLUG (4 letters). A NAG is an old or worn-out horse, usually used for riding or pulling a cart. It is also used to describe someone who constantly complains or finds fault with others. A PLUG is an old horse that is used for hard labor, such as plowing fields or hauling heavy loads. The term DECREPIT HORSE is often used to describe an animal that is no longer useful due to its age and condition.