Peninsular Malaysia vs Malaya

Peninsular Malaysia and Malaya both are nouns.

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

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

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

Other synonyms of Peninsular Malaysia include West Malaysia.

Peninsular Malaysia (noun)	Malaya (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