What Does It Mean?

You are correct!

From our dictionary:
pro•te•an

(prO'tEun, prO•tE'-), adj.
1. readily assuming different forms or characters; extremely variable.
2. changeable in shape or form, as an amoeba.
3. (of an actor or actress) versatile; able to play many kinds of roles.
4. (cap.) of, pertaining to, or suggestive of Proteus.