placard vs posting

placard and posting both are nouns.

Word	Noun	Adjective	Verb	Adverb
placard	Yes	No	Yes	No
posting	Yes	No	No	No

As nouns, placard and posting are synonyms defined as:

placard and posting: a sign posted in a public place as an advertisement

Other synonyms of placard include bill, card, notice, poster.

placard (noun)	posting (noun)
a sign posted in a public place as an advertisement	the transmission of a letter
	a sign posted in a public place as an advertisement
	(bookkeeping) a listing on the company's records

placard (verb)	posting (verb)
publicize or announce by placards
post in a public place