harbor vs seaport

harbor and seaport both are nouns.

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

As nouns, harbor and seaport are synonyms defined as:

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

Other synonyms of harbor include harbour, haven.

harbor (noun)	seaport (noun)
a place of refuge and comfort and security	a sheltered port where ships can take on or discharge cargo
a sheltered port where ships can take on or discharge cargo

harbor (verb)	seaport (verb)
maintain (a theory, thoughts, or feelings)
hold back a thought or feeling about
keep in one's possession; of animals
secretly shelter (as of fugitives or criminals)