Beginner

Never has had a lessons or only a couple. Tentative around water or no fear  with no ability in the water. Will put face in the water but not all the time. Uses the bicycle kick.

Intermediate

Has had some lessons. Can put face in and blow
bubbles continuously while swimming. No bicycle kick, uses flutter kick, learning whip kick. Working on rhythmic breathing. Comfortable in the water on front and back.     

Advanced

Know strokes but lacks cleanness (splashy) while
performing strokes. Fairly smooth and horizontal in water. Practice will focus on technique and refinement of strokes.