mental quickness vs quickness

mental quickness and quickness both are nouns.

Word	Noun	Adjective	Verb	Adverb
mental quickness	Yes	No	No	No
quickness	Yes	No	No	No

As nouns, mental quickness and quickness are synonyms defined as:

mental quickness and quickness: intelligence as revealed by an ability to give correct responses without delay

Other synonyms of mental quickness include quick-wittedness.

mental quickness (noun)	quickness (noun)
intelligence as revealed by an ability to give correct responses without delay	a rate that is rapid
	intelligence as revealed by an ability to give correct responses without delay
	skillful performance or ability without difficulty