weak spot vs weak part

weak spot and weak part both are nouns.

Word	Noun	Adjective	Verb	Adverb
weak spot	Yes	No	No	No
weak part	Yes	No	No	No

As nouns, weak spot and weak part are synonyms defined as:

Other synonyms of weak spot include soft spot.

weak spot (noun)	weak part (noun)
a place of especial vulnerability	a place of especial vulnerability