in love vs smitten

in love and smitten both are adjectives.

Word	Noun	Adjective	Verb	Adverb
in love	No	Yes	No	No
smitten	No	Yes	No	No

As adjectives, in love and smitten are synonyms defined as:

Other synonyms of in love include enamored, infatuated, potty, soft on, taken with.

in love (adjective)	smitten (adjective)
marked by foolish or unreasoning fondness	(used in combination) affected by something overwhelming
	marked by foolish or unreasoning fondness