casual, reckless, disorder

胡 is composed of 古 (ancient) and the radical 肉 (flesh). 古 signifies age; as humans age and their skin loses elasticity, the flesh under the jaw becomes loose and sags. Thus, the original meaning of 胡 is the dewlap or flesh under the chin. Because this area is covered with hair, 胡 also came to denote the beard under the chin—a meaning later specified by the character 鬍. If a beard is left untrimmed to grow freely, it becomes messy and unkempt; hence, 胡 extended to mean recklessly, arbitrarily, or without order.