inclemency vs overcast

inclemency and overcast both are nouns.

Word	Noun	Adjective	Verb	Adverb
inclemency	Yes	No	No	No
overcast	Yes	Yes	Yes	No

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

Other hyponyms of inclemency include raw weather, storminess, cloud cover, cloudiness, turbulence.

inclemency (noun)	overcast (noun)
excessive sternness	a cast that falls beyond the intended spot
weather unsuitable for outdoor activities	a long whipstitch or overhand stitch overlying an edge to prevent raveling
	the state of the sky when it is covered by clouds
	gloomy semidarkness caused by cloud cover

inclemency (adjective)	overcast (adjective)
	filled or abounding with clouds

inclemency (verb)	overcast (verb)
	sew with an overcast stitch from one section to the next
	sew over the edge of with long slanting wide stitches
	make overcast or cloudy