palate vs roof of the mouth

palate and roof of the mouth both are nouns.

Word	Noun	Adjective	Verb	Adverb
palate	Yes	No	No	No
roof of the mouth	Yes	No	No	No

As nouns, palate and roof of the mouth are synonyms defined as:

palate and roof of the mouth: the upper surface of the mouth that separates the oral and nasal cavities

palate (noun)	roof of the mouth (noun)
the upper surface of the mouth that separates the oral and nasal cavities	the upper surface of the mouth that separates the oral and nasal cavities