increase vs step-up

increase and step-up both are nouns.

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

As nouns, increase and step-up are synonyms defined as:

increase (noun)	step-up (noun)
the act of increasing something	the act of increasing something
the amount by which something increases
a change resulting in an increase
a process of becoming larger or longer or more numerous or more important
a quantity that is added

increase (verb)	step-up (verb)
become bigger or greater in amount
make bigger or more