rarely vs rare

rarely is not an adjective while rare is an adjective.

Word	Noun	Adjective	Verb	Adverb
rarely	No	No	No	Yes
rare	No	Yes	No	No

rarely (adjective)	rare (adjective)
	marked by an uncommon quality; especially superlative or extreme of its kind
	recurring only at long intervals
	(of meat) cooked a short time; still red inside
	not widely distributed
	having low density
	not widely known; especially valued for its uncommonness

rarely (adverb)	rare (adverb)
not often