extenuation vs step-down

extenuation and step-down both are nouns.

Word	Noun	Adjective	Verb	Adverb
extenuation	Yes	No	No	No
step-down	Yes	No	No	No

As nouns, step-down is a hypernym of extenuation; that is, step-down is a word with a broader meaning than extenuation:

extenuation: to act in such a way as to cause an offense to seem less serious
step-down: the act of decreasing or reducing something

Other hypernyms of extenuation include decrease, diminution, reduction.

extenuation (noun)	step-down (noun)
to act in such a way as to cause an offense to seem less serious	the act of decreasing or reducing something
a partial excuse to mitigate censure; an attempt to represent an offense as less serious than it appears by showing mitigating circumstances