West Malaysia vs Peninsular Malaysia

West Malaysia and Peninsular Malaysia both are nouns.

Word	Noun	Adjective	Verb	Adverb
West Malaysia	Yes	No	No	No
Peninsular Malaysia	Yes	No	No	No

As nouns, West Malaysia and Peninsular Malaysia are synonyms defined as:

West Malaysia and Peninsular Malaysia: the region of Malaysia on the Malay Peninsula; shares a land border with Thailand to the north

Other synonyms of West Malaysia include Malaya.

West Malaysia (noun)	Peninsular Malaysia (noun)
the region of Malaysia on the Malay Peninsula; shares a land border with Thailand to the north	the region of Malaysia on the Malay Peninsula; shares a land border with Thailand to the north