sideburn vs side-whiskers

sideburn and side-whiskers both are nouns.

Word	Noun	Adjective	Verb	Adverb
sideburn	Yes	No	No	No
side-whiskers	Yes	No	No	No

As nouns, sideburn and side-whiskers are synonyms defined as:

sideburn and side-whiskers: facial hair that has grown down the side of a man's face in front of the ears (especially when the rest of the beard is shaved off)

Other synonyms of sideburn include burnside, mutton chop.

sideburn (noun)	side-whiskers (noun)
facial hair that has grown down the side of a man's face in front of the ears (especially when the rest of the beard is shaved off)	facial hair that has grown down the side of a man's face in front of the ears (especially when the rest of the beard is shaved off)