platyrrhinian vs New World monkey

platyrrhinian and New World monkey both are nouns.

Word	Noun	Adjective	Verb	Adverb
platyrrhinian	Yes	Yes	No	No
New World monkey	Yes	No	No	No

As nouns, platyrrhinian and New World monkey are synonyms defined as:

platyrrhinian and New World monkey: hairy-faced arboreal monkeys having widely separated nostrils and long usually prehensile tails

Other synonyms of platyrrhinian include platyrrhine.

platyrrhinian (noun)	New World monkey (noun)
hairy-faced arboreal monkeys having widely separated nostrils and long usually prehensile tails	hairy-faced arboreal monkeys having widely separated nostrils and long usually prehensile tails

platyrrhinian (adjective)	New World monkey (adjective)
of or related to New World monkeys having nostrils far apart or to people with broad noses