post vs mail

post and mail both are nouns.

Word	Noun	Adjective	Verb	Adverb
post	Yes	No	Yes	No
mail	Yes	No	Yes	No

As nouns, post and mail are synonyms defined as:

post and mail: the system whereby messages are transmitted via the post office

Other synonyms of post include mail service, postal service.

As nouns, post and mail are synonyms defined as:

post and mail: any particular collection of letters or packages that is delivered

As verbs, post and mail are synonyms defined as:

Other synonyms of post include send.

post (noun)	mail (noun)
a job in an organization	(Middle Ages) flexible armor made of interlinked metal rings
the delivery and collection of letters and packages	a conveyance that transports the letters and packages that are conveyed by the postal system
an upright consisting of a piece of timber or metal fixed firmly in an upright position	the system whereby messages are transmitted via the post office
military installation at which a body of troops is stationed	the bags of letters and packages that are transported by the postal service
the system whereby messages are transmitted via the post office	any particular collection of letters or packages that is delivered
a pole or stake set up to mark something (as the start or end of a race track)
A message on a social media website
any particular collection of letters or packages that is delivered
the position where someone (as a guard or sentry) stands or is assigned to stand

post (verb)	mail (verb)
display, as of records in sports games	cause to be directed or transmitted to another place
mark or expose as infamous	send via the postal service
cause to be directed or transmitted to another place
publicize with, or as if with, a poster
To post a message on a social media website
assign to a station
place so as to be noticed
mark with a stake
affix in a public place or for public notice
ride Western style and bob up and down in the saddle in rhythm with a horse's trotting gait
transfer (entries) from one account book to another
enter on a public list
assign to a post; put into a post