Take a look at the ASWB Knowledge, Skills, and Abilities outline, section 1B, Human Behavior in the Environment. You'll find a bunch of basic social work stuff that you've probably learned at some point during social work school, working, or even in an undergraduate Psych 101 course. This bullet pointed item may have shown up in all three: "Psychological Defense Mechanisms." "Psychological" as opposed to swords and shields, we guess.
Getting prepared for defense mechanism questions on the social work licensing exam is simple. Just look over a list of defense mechanisms and some examples. We're not going to retype it all for you but are happy to provide some helpful links and this chart via Simply Psychology. First, a few of the the most common defense mechanisms:
Next, lists and explanation aplenty: