antacid vs antiacid

antacid and antiacid both are nouns.

Word	Noun	Adjective	Verb	Adverb
antacid	Yes	Yes	No	No
antiacid	Yes	No	No	No

As nouns, antacid and antiacid are synonyms defined as:

antacid and antiacid: an agent that counteracts or neutralizes acidity (especially in the stomach)

Other synonyms of antacid include alkaliser, alkalizer, gastric antacid.

antacid (noun)	antiacid (noun)
an agent that counteracts or neutralizes acidity (especially in the stomach)	an agent that counteracts or neutralizes acidity (especially in the stomach)

antacid (adjective)	antiacid (adjective)
acting to neutralize acid (especially in the stomach)