Luminal vs purple heart

Luminal and purple heart both are nouns.

Word	Noun	Adjective	Verb	Adverb
Luminal	Yes	No	No	No
purple heart	Yes	No	No	No

As nouns, Luminal and purple heart are synonyms defined as:

Other synonyms of Luminal include phenobarbital, phenobarbitone, sodium thiopental.

Luminal (noun)	purple heart (noun)
a long-acting barbiturate used as a sedative	a long-acting barbiturate used as a sedative