clinician vs practitioner

clinician and practitioner both are nouns.

Word	Noun	Adjective	Verb	Adverb
clinician	Yes	No	No	No
practitioner	Yes	No	No	No

As nouns, practitioner is a hypernym of clinician; that is, practitioner is a word with a broader meaning than clinician:

clinician: a practitioner (of medicine or psychology) who does clinical work instead of laboratory experiments
practitioner: someone who practices a learned profession

Other hypernyms of clinician include practician.

clinician (noun)	practitioner (noun)
a practitioner (of medicine or psychology) who does clinical work instead of laboratory experiments	someone who practices a learned profession