Just to clarify some of the confusion above, one must have a PhD or PsyD degree to be referred to as a "clinical psychologist" or "psychologist" in a professional setting. This is stated in the APA Ethics Guidelines, and is overseen by state licensing boards.
So, in other words, there is no such thing as a "master's level psychologist." Moreover, a doctoral candidate in psychology is prohibited from using the title "psychologist" or "clinical psychologist" until graduation. Again, this is stipulated in the APA ethics guidelines. Indeed, according to the APA, it is even misleading to refer to oneself as "doctoral candidate in psychology" because the general public may not be educated enough to understand this statement. It even comes up as a question on the EPPP - it was on all of the practice exams! 🙄
However, my understanding is that there is no oversight for the use of terms such as: psychotherapist, therapist, counselor, clinician, etc.