preliminary vs exploratory

preliminary is a noun but exploratory is not a noun.

Word	Noun	Adjective	Verb	Adverb
preliminary	Yes	Yes	No	No
exploratory	No	Yes	No	No

preliminary (noun)	exploratory (noun)
a minor match preceding the main event
something that serves as a preceding event or introduces what follows

preliminary (adjective)	exploratory (adjective)
denoting an action or event preceding or in preparation for something more important	serving in or intended for exploration or discovery