weak spot vs soft spot

weak spot and soft spot both are nouns.

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

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

Other synonyms of weak spot include weak part.

weak spot (noun)	soft spot (noun)
a place of especial vulnerability	a place of especial vulnerability
	any membranous gap between the bones of the cranium in an infant or fetus
	a sentimental affection