wise guy vs wiseacre

wise guy and wiseacre both are nouns.

Word	Noun	Adjective	Verb	Adverb
wise guy	Yes	No	No	No
wiseacre	Yes	No	No	No

As nouns, wise guy and wiseacre are synonyms defined as:

wise guy and wiseacre: an upstart who makes conceited, sardonic, insolent comments

Other synonyms of wise guy include smart aleck, weisenheimer, wisenheimer.

wise guy (noun)	wiseacre (noun)
an upstart who makes conceited, sardonic, insolent comments	an upstart who makes conceited, sardonic, insolent comments