productiveness vs fecundity

productiveness and fecundity both are nouns.

Word	Noun	Adjective	Verb	Adverb
productiveness	Yes	No	No	No
fecundity	Yes	No	No	No

As nouns, fecundity is a hypernym of productiveness; that is, fecundity is a word with a broader meaning than productiveness:

productiveness: the quality of being productive or having the power to produce
fecundity: the quality of something that causes or assists healthy growth

Other hypernyms of productiveness include fruitfulness.

productiveness (noun)	fecundity (noun)
the quality of being productive or having the power to produce	the quality of something that causes or assists healthy growth
	the intellectual productivity of a creative imagination
	the state of being fertile; capable of producing offspring