I have a slightly different take on the question and thus the reply.
Commonly students ask about Yoga when they really mean asana. Equally common (here) is an underabundance of background information. If the student only has an asana practice and that practice spans less than two years (again we do not know if that is once per week or twice per day) I would tend not to direct them to the vedas, the pradipika, etcetera. I think it’s a bit overwhelming and perhaps even misleading as the mind of the beginner often is unprepared for the load.
It is also important to mention that the variance in practices can bear greatly on the answer to this question. For example an intermediate kundalini student would not be operating under the same definition as an intermediate Bikram student. An intermediate viniyoga student would not be using the same pamphlet as an intermediate ashtanga student, and so on.
What does this mean? Basically it means ask your teacher(s). I can however tell you what I believe an intermediate student is in the alignment-based practice I teach (Purna Yoga™).
That student has foundational safety elements in asana etched in their consciousness such that they align the knee properly in standing poses, protect the back, and maintain the integrity of the neck. That student is able to contract muscles while releasing others, can use the serratus anterior to abduct the scapulae, remains focused without being distracted by external stimulus, understands the concepts and has the ability to place the mind in the body and moves the breath to that placement. That student understands the nature of ego and how to transform it through the practice, begins taking their practice off the mat and applying it in their living, has a grasp of Yamas and Niyamas, and begins to more carefully see what choices they make and the outcomes they lead to.
This to me is a bit of a description of an intermediate student, and I’ve left quite a bit out.