rate vs downgrade

rate and downgrade both are nouns.

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

As verbs, downgrade is a hyponym of rate; that is, downgrade is a word with a more specific, narrower meaning than rate:

rate (noun)	downgrade (noun)
the relative speed of progress or change	the property possessed by a slope or surface that descends
amount of a charge or payment relative to some basis
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

rate (verb)	downgrade (verb)
assign a rank or rating to	rate lower; lower in value or esteem
estimate the value of
be worthy of or have a certain rating