There are several synonyms for the term "young horse." Some of these include foal, filly, colt, yearling, and weanling. A foal is a horse that is less than one year old, while a filly is a female horse that is less than four years old. A colt is a male horse that is less than four years old. A yearling is any horse that is between one and two years old, and a weanling is a horse that has been recently separated from its mother. Knowing these synonyms can be useful for horse enthusiasts and those looking to purchase a young horse.