clearing vs improvement

clearing and improvement both are nouns.

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

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

clearing (noun)	improvement (noun)
the act of freeing from suspicion	the act of improving something
the act of removing solid particles from a liquid	a change for the better; progress in development
a tract of land with few or no trees in the middle of a wooded area	a condition superior to an earlier condition