decompressing vs alleviation

decompressing and alleviation both are nouns.

Word	Noun	Adjective	Verb	Adverb
decompressing	Yes	No	No	No
alleviation	Yes	No	No	No

As nouns, alleviation is a hypernym of decompressing; that is, alleviation is a word with a broader meaning than decompressing:

decompressing: relieving pressure (especially bringing a compressed person gradually back to atmospheric pressure)
alleviation: the act of reducing something unpleasant (as pain or annoyance)

Other hypernyms of decompressing include easement, easing, relief.

decompressing (noun)	alleviation (noun)
relieving pressure (especially bringing a compressed person gradually back to atmospheric pressure)	the act of reducing something unpleasant (as pain or annoyance)
	the feeling that comes when something burdensome is removed or reduced