recovery vs improvement

recovery and improvement both are nouns.

Word	Noun	Adjective	Verb	Adverb
recovery	Yes	No	No	No
improvement	Yes	No	No	No

As nouns, improvement is a hypernym of recovery; that is, improvement is a word with a broader meaning than recovery:

Other hypernyms of recovery include advance, betterment.

recovery (noun)	improvement (noun)
the act of regaining or saving something lost (or in danger of becoming lost)	the act of improving something
return to an original state	a change for the better; progress in development
gradual healing (through rest) after sickness or injury	a condition superior to an earlier condition