sweetheart vs stunner

sweetheart and stunner both are nouns.

Word	Noun	Adjective	Verb	Adverb
sweetheart	Yes	Yes	No	No
stunner	Yes	No	No	No

As nouns, sweetheart and stunner are synonyms defined as:

Other synonyms of sweetheart include beauty, dish, knockout, looker, lulu, mantrap, peach, ravisher, smasher.

sweetheart (noun)	stunner (noun)
a person loved by another person	an unexpected and amazing event
a very attractive or seductive looking woman	a very attractive or seductive looking woman
any well-liked individual
a beloved person; used as terms of endearment

sweetheart (adjective)	stunner (adjective)
privileged treatment of a favored person or corporation (sometimes unethically)