Meaning : The act of relieving ills and changing for the better.
Synonyms : amelioration, betterment
Meaning : A condition superior to an earlier condition.
Example :
The new school represents a great improvement.
Synonyms : improvement
A condition inferior to an earlier condition. A gradual falling off from a better state.
declination, declineMeaning : The linguistic process in which over a period of time a word grows more positive in connotation or more elevated in meaning.