antacid vs incompatible

antacid is a noun but incompatible is not a noun.

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

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

antacid (adjective)	incompatible (adjective)
acting to neutralize acid (especially in the stomach)	used especially of drugs or muscles that counteract or neutralize each other's effect
	not compatible
	incapable of being used with or connected to other devices or components without modification
	not suitable to your tastes or needs
	of words so related that one contrasts with the other
	used especially of solids or solutions; incapable of blending into a stable homogeneous mixture
	not in keeping with what is correct or proper
	not compatible with other facts
	not easy to combine harmoniously