antipodal vs antipodean

antipodal is a noun but antipodean is not a noun.

Word	Noun	Adjective	Verb	Adverb
antipodal	Yes	Yes	No	No
antipodean	No	Yes	No	No

As adjectives, antipodal and antipodean are synonyms defined as:

antipodal and antipodean: relating to the antipodes or situated at opposite sides of the earth

antipodal (noun)	antipodean (noun)
the relation of opposition along a diameter

antipodal (adjective)	antipodean (adjective)
relating to the antipodes or situated at opposite sides of the earth	relating to the antipodes or situated at opposite sides of the earth