overcharge vs rob

overcharge is a noun but rob is not a noun.

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

As verbs, overcharge and rob are synonyms defined as:

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

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

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