quickness vs mental quickness

quickness and mental quickness both are nouns.

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

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

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

Other synonyms of quickness include quick-wittedness.

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