oftenness vs frequency

oftenness and frequency both are nouns.

Word	Noun	Adjective	Verb	Adverb
oftenness	Yes	No	No	No
frequency	Yes	No	No	No

As nouns, oftenness and frequency are synonyms defined as:

oftenness and frequency: the number of occurrences within a given time period

Other synonyms of oftenness include frequence.

oftenness (noun)	frequency (noun)
the number of occurrences within a given time period	the number of observations in a given statistical category
	the ratio of the number of observations in a statistical category to the total number of observations
	the number of occurrences within a given time period