Final answer:
The attorney throwing items around exhibits regression, which is reverting to immature behaviors when faced with stress.
Step-by-step explanation:
The behavior of the attorney who throws books and furniture around after losing a case most likely represents the use of the regression defense mechanism. Regression is a defense mechanism in which a person confronted with anxiety returns to a more immature behavioral stage. This is seen in the case of the attorney who reverts to child-like tantrums of physical outbursts, as an inability to cope with the feelings of defeat and frustration in a mature way.