holy oil vs balm

holy oil and balm both are nouns.

Word	Noun	Adjective	Verb	Adverb
holy oil	Yes	No	No	No
balm	Yes	No	No	No

As nouns, balm is a hypernym of holy oil; that is, balm is a word with a broader meaning than holy oil:

holy oil: a consecrated ointment consisting of a mixture of oil and balsam
balm: semisolid preparation (usually containing a medicine) applied externally as a remedy or for soothing an irritation

Other hypernyms of holy oil include ointment, salve, unction, unguent.

holy oil (noun)	balm (noun)
a consecrated ointment consisting of a mixture of oil and balsam	semisolid preparation (usually containing a medicine) applied externally as a remedy or for soothing an irritation
	any of various aromatic resinous substances used for healing and soothing