An OBSTINATE BEAST is an animal that is stubborn and difficult to control. The term can be broken down into three parts: OBSTINATE, BEAST, and ASS. The first part, OBSTINATE, means to be stubbornly persistent in adhering to an opinion, purpose, or course of action. The second part, BEAST, refers to a large, four-legged animal, such as a horse or cow. The third part, ASS, is a three-letter word for a donkey or mule. Together, these three words form the phrase 'OBSTINATE BEAST, ' which describes an animal that is difficult to control due to its stubbornness.