appreciation vs step-up

appreciation and step-up both are nouns.

Word	Noun	Adjective	Verb	Adverb
appreciation	Yes	No	No	No
step-up	Yes	No	No	No

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

Other hypernyms of appreciation include increase.

appreciation (noun)	step-up (noun)
a favorable judgment	the act of increasing something
an increase in price or value
understanding of the nature or meaning or quality or magnitude of something
delicate discrimination (especially of esthetic values)
an expression of gratitude