snarl-up vs traffic jam

snarl-up and traffic jam both are nouns.

Word	Noun	Adjective	Verb	Adverb
snarl-up	Yes	No	No	No
traffic jam	Yes	No	No	No

As nouns, snarl-up and traffic jam are synonyms defined as:

snarl-up and traffic jam: a number of vehicles blocking one another until they can scarcely move

snarl-up (noun)	traffic jam (noun)
a number of vehicles blocking one another until they can scarcely move	a number of vehicles blocking one another until they can scarcely move