inattentiveness vs inattention

inattentiveness and inattention both are nouns.

Word	Noun	Adjective	Verb	Adverb
inattentiveness	Yes	No	No	No
inattention	Yes	No	No	No

As nouns, inattention is a hypernym of inattentiveness; that is, inattention is a word with a broader meaning than inattentiveness:

inattentiveness: a lack of attentiveness (as to children or helpless people)
inattention: lack of attention

inattentiveness (noun)	inattention (noun)
the trait of not being considerate and thoughtful of others	lack of attention
a lack of attentiveness (as to children or helpless people)