expert vs proficient

expert is a noun but proficient is not a noun.

Word	Noun	Adjective	Verb	Adverb
expert	Yes	Yes	No	No
proficient	No	Yes	No	No

As adjectives, expert and proficient are synonyms defined as:

expert and proficient: having or showing knowledge and skill and aptitude

Other synonyms of expert include adept, good, practiced, skilful, skillful.

expert (noun)	proficient (noun)
a person with special knowledge or ability who performs skillfully

expert (adjective)	proficient (adjective)
having or showing knowledge and skill and aptitude	of or relating to technique or proficiency in a practical skill
of or relating to or requiring special knowledge to be understood	having or showing knowledge and skill and aptitude