seaport vs haven

seaport and haven both are nouns.

Word	Noun	Adjective	Verb	Adverb
seaport	Yes	No	No	No
haven	Yes	No	No	No

As nouns, seaport and haven are synonyms defined as:

seaport and haven: a sheltered port where ships can take on or discharge cargo

Other synonyms of seaport include harbor, harbour.

seaport (noun)	haven (noun)
a sheltered port where ships can take on or discharge cargo	a shelter serving as a place of safety or sanctuary
	a sheltered port where ships can take on or discharge cargo