adversity vs extremity

adversity and extremity both are nouns.

Word	Noun	Adjective	Verb	Adverb
adversity	Yes	No	No	No
extremity	Yes	No	No	No

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

adversity: a state of misfortune or affliction
extremity: an extreme condition or state (especially of adversity or disease)

Other hyponyms of adversity include ill-being, catastrophe, disaster, distress, affliction, victimization, low-water mark, nadir.

adversity (noun)	extremity (noun)
a stroke of ill fortune; a calamitous event	an external body part that projects from the body
a state of misfortune or affliction	that part of a limb that is farthest from the torso
	the outermost or farthest region or point
	the greatest or utmost degree
	an extreme condition or state (especially of adversity or disease)