mercurial ointment vs ointment

mercurial ointment and ointment both are nouns.

Word	Noun	Adjective	Verb	Adverb
mercurial ointment	Yes	No	No	No
ointment	Yes	No	No	No

As nouns, ointment is a hypernym of mercurial ointment; that is, ointment is a word with a broader meaning than mercurial ointment:

mercurial ointment: an ointment containing mercury
ointment: semisolid preparation (usually containing a medicine) applied externally as a remedy or for soothing an irritation

Other hypernyms of mercurial ointment include balm, salve, unction, unguent.

mercurial ointment (noun)	ointment (noun)
an ointment containing mercury	semisolid preparation (usually containing a medicine) applied externally as a remedy or for soothing an irritation
	toiletry consisting of any of various substances in the form of a thick liquid that have a soothing and moisturizing effect when applied to the skin