Let's suppose I know a person who is an expert on a certain subject, say history. Since I like history myself, I will ask him/her a number of questions on subjects that I know only superficially: I studied them in school but I have now almost no remembrance of those facts and of what they implied. This person will usually answer me with details but, from time to time, I find him/her unable to answer. Although it is clear to me (and probably to others) that s/he does not have the knowledge, or the understanding, to actually answer the question, s/he actually makes up some excuses such as that it is a complicated argument, or that I would not be able to understand it because I am no expert (implying that s/he is).
To my eyes, this person is not only avoiding to face an issue, but also suppressing it in such a way that something that should be a chance to learn becomes actually a change to boost the ego.
Would this be an avoidance behaviour/disorder? Is there any other more specific definition to describe that mechanism?