red hot vs hot dog

red hot and hot dog both are nouns.

Word	Noun	Adjective	Verb	Adverb
red hot	Yes	No	No	No
hot dog	Yes	No	No	No

As nouns, red hot and hot dog are synonyms defined as:

Other synonyms of red hot include hotdog.

red hot (noun)	hot dog (noun)
a frankfurter served hot on a bun	a smooth-textured sausage of minced beef or pork usually smoked; often served on a bread roll
	a frankfurter served hot on a bun
	someone who performs dangerous stunts to attract attention to himself