Collectible can be used as an adjective and a noun.
The adjective form mean something that is able to be collected.
The noun form means something that is collected such as stamps or art.
The part of speech for this particular word is a noun.
part of speech
The part of speech for "answer" is a noun.
what part of speech is beneath
adverb
The part of speech for "explicit" is an adjective.
The part of speech for "lecturer" is a noun.
The part of speech for "rapid" is an adjective.
The part of speech for "breezy" is an adjective.
The part of speech for "buried" is a verb.
The part of speech for "indefinite" is an adjective.
The part of speech for "unfamiliar" is an adjective.