impediment vs occlusion

impediment and occlusion both are nouns.

Word	Noun	Adjective	Verb	Adverb
impediment	Yes	No	No	No
occlusion	Yes	No	No	No

As nouns, occlusion is a hyponym of impediment; that is, occlusion is a word with a more specific, narrower meaning than impediment:

impediment (noun)	occlusion (noun)
any structure that makes progress difficult	the act of blocking
something immaterial that interferes with or delays action or progress	an obstruction in a pipe or tube
	(dentistry) the normal spatial relation of the teeth when the jaws are closed
	(meteorology) a composite front when colder air surrounds a mass of warm air and forces it aloft
	closure or blockage (as of a blood vessel)