skillful vs expert

skillful is not a noun while expert is a noun.

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

As adjectives, skillful and expert are synonyms defined as:

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

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

skillful (adjective)	expert (adjective)
done with delicacy and skill	having or showing knowledge and skill and aptitude
having or showing knowledge and skill and aptitude	of or relating to or requiring special knowledge to be understood