palliative vs alleviatory

palliative is a noun but alleviatory is not a noun.

Word	Noun	Adjective	Verb	Adverb
palliative	Yes	Yes	No	No
alleviatory	No	Yes	No	No

As adjectives, palliative and alleviatory are synonyms defined as:

palliative and alleviatory: moderating pain or sorrow by making it easier to bear

Other synonyms of palliative include alleviative, lenitive, mitigative, mitigatory.

palliative (noun)	alleviatory (noun)
remedy that alleviates pain without curing

palliative (adjective)	alleviatory (adjective)
moderating pain or sorrow by making it easier to bear	moderating pain or sorrow by making it easier to bear