soft spot vs fontanel

soft spot and fontanel both are nouns.

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

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

soft spot and fontanel: any membranous gap between the bones of the cranium in an infant or fetus

Other synonyms of soft spot include fontanelle.

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