sluggishness vs rate

sluggishness and rate both are nouns.

Word	Noun	Adjective	Verb	Adverb
sluggishness	Yes	No	No	No
rate	Yes	No	Yes	No

As nouns, rate is a hypernym of sluggishness; that is, rate is a word with a broader meaning than sluggishness:

Other hypernyms of sluggishness include pace.

sluggishness (noun)	rate (noun)
inactivity; showing an unusual lack of energy	the relative speed of progress or change
the pace of things that move relatively slowly	amount of a charge or payment relative to some basis
a state of comatose torpor (as found in sleeping sickness)	a quantity or amount or measure considered as a proportion of another quantity or amount or measure
	a magnitude or frequency relative to a time unit

sluggishness (verb)	rate (verb)
	assign a rank or rating to
	estimate the value of
	be worthy of or have a certain rating