open vs exterior

open and exterior both are nouns.

Word	Noun	Adjective	Verb	Adverb
open	Yes	Yes	Yes	No
exterior	Yes	Yes	No	No

As nouns, exterior is a hypernym of open; that is, exterior is a word with a broader meaning than open:

Other hypernyms of open include outside.

open (noun)	exterior (noun)
information that has become public	the outer side or surface of something
a tournament in which both professionals and amateurs may play	the region that is outside of something
a clear or unobstructed space or expanse of land or water
where the air is unconfined

open (adjective)	exterior (adjective)
ready or willing to receive favorably	situated in or suitable for the outdoors or outside of a building
affording unobstructed entrance and exit; not shut or closed
affording free passage or access
(set theory) of an interval that contains neither of its endpoints
open and observable; not secret or hidden
used of mouth or eyes
ready for business
not having been filled
(of textures) full of small openings or gaps
openly straightforward and direct without reserve or secretiveness
not requiring union membership
open to or in view of all
possibly accepting or permitting
without undue constriction as from e.g. tenseness or inhibition
having no protecting cover or enclosure
affording free passage or view
with no protection or shield
accessible to all
not sealed or having been unsealed
not brought to a conclusion; subject to further thought
not defended or capable of being defended

open (verb)	exterior (verb)
make available
become available
make the opening move
cause to open or to become open
become open
spread out or open from a closed or folded state
display the contents of a file or start an application as on a computer
afford access to
start to operate or function or cause to start operating or functioning
begin or set in action, of meetings, speeches, recitals, etc.
have an opening or passage or outlet