rob vs overcharge

rob is not a noun while overcharge is a noun.

Word	Noun	Adjective	Verb	Adverb
rob	No	No	Yes	No
overcharge	Yes	No	Yes	No

As verbs, rob and overcharge are synonyms defined as:

Other synonyms of rob include fleece, gazump, hook, pluck, plume, soak, surcharge.

rob (noun)	overcharge (noun)
	a price that is too high

rob (verb)	overcharge (verb)
take something away by force or without the consent of the owner	place too much a load on
rip off; ask an unreasonable price	rip off; ask an unreasonable price