Sometimes students think that this discussion of types of language is about vocabulary, but it's not. You don't need a fancy vocabulary to come up with bent spoon or limping dog or Mary told Margaret she hates me . It's not about imagination, either. If you have reached any kind of a reasoned conclusion, you must have had or read about or heard about relevant experiences. Finding concrete specifics doesn't require a big vocabulary or a vivid imagination, just the willingness to recall what you already know. If you really can't find any examples or specifics to support your general conclusion, chances are you don't really know what you're talking about (and we are all guilty of that more than we care to admit).
Does not matter what topic you will choose, what is really important: really believe that you will find your audience. The topic that you are going to choose needs to be interesting for you personally, in other case it would be really difficult to gather all facts and general information to make a good paper. You need to ask yourself: will my future work be interesting to read? Has my future essay a perspective to become a reason for discussion? Is it possible to be serious in talking about this theme but not so much serious to put to sleep this one, who will read it? If the answers are yes, you have a good chance to write an outstanding definition essay.