sassing vs back talk

sassing and back talk both are nouns.

Word	Noun	Adjective	Verb	Adverb
sassing	Yes	No	No	No
back talk	Yes	No	No	No

As nouns, sassing and back talk are synonyms defined as:

Other synonyms of sassing include backtalk, lip, mouth, sass.

sassing (noun)	back talk (noun)
an impudent or insolent rejoinder	an impudent or insolent rejoinder