overcrowd vs surcharge

overcrowd is not a noun while surcharge is a noun.

Word	Noun	Adjective	Verb	Adverb
overcrowd	No	No	Yes	No
surcharge	Yes	No	Yes	No

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

overcrowd (noun)	surcharge (noun)
	an additional charge (as for items previously omitted or as a penalty for failure to exercise common caution or common skill)

overcrowd (verb)	surcharge (verb)
crowd together too much	show an omission in (an account) for which credit ought to have been given
cause to crowd together too much	fill to an excessive degree
	place too much a load on
	print a new denomination on a stamp or a banknote
	fill to capacity with people
	rip off; ask an unreasonable price
	charge an extra fee, as for a special service