reparation vs improvement

reparation and improvement both are nouns.

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

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

reparation (noun)	improvement (noun)
something done or paid in expiation of a wrong	the act of improving something
the act of putting something in working order again	a change for the better; progress in development
(usually plural) compensation exacted from a defeated nation by the victors	a condition superior to an earlier condition
compensation (given or received) for an insult or injury