white pepper vs Madagascar pepper

white pepper and Madagascar pepper both are nouns.

Word	Noun	Adjective	Verb	Adverb
white pepper	Yes	No	No	No
Madagascar pepper	Yes	No	No	No

As nouns, white pepper and Madagascar pepper are synonyms defined as:

white pepper and Madagascar pepper: climber having dark red berries (peppercorns) when fully ripe; southern India and Sri Lanka; naturalized in northern Burma and Assam

Other synonyms of white pepper include black pepper, common pepper, pepper, Piper nigrum.

white pepper (noun)	Madagascar pepper (noun)
pepper ground from husked peppercorns	climber having dark red berries (peppercorns) when fully ripe; southern India and Sri Lanka; naturalized in northern Burma and Assam
climber having dark red berries (peppercorns) when fully ripe; southern India and Sri Lanka; naturalized in northern Burma and Assam