Unexplained technical term. When you use a term in an unusual or special sense, it is necessary to explain exactly what you take the term to mean. Failure to do this prevents the reader from fully understanding your point. Problems of intelligibility occur when one uses a term or makes a point that is obscure or ambiguous. This problem can be avoided by a more clear and precise formulation of one's points.
Words mean something.
I write this when you seem to assume that words mean nothing or can mean anything one chooses they shall mean, or one of the many variations on this error. Never assume that the reader knows your mind. Only you know what you're thinking. Try to write in as simple and unambiguous a way as you can. Clarity is a major goal in writing.