country music vs country and western

country music and country and western both are nouns.

Word	Noun	Adjective	Verb	Adverb
country music	Yes	No	No	No
country and western	Yes	No	No	No

As nouns, country music and country and western are synonyms defined as:

country music and country and western: a simple style of folk music heard mostly in the southern United States; usually played on stringed instruments

Other synonyms of country music include C and W.

country music (noun)	country and western (noun)
a simple style of folk music heard mostly in the southern United States; usually played on stringed instruments	a simple style of folk music heard mostly in the southern United States; usually played on stringed instruments