callously vs inattentively

callously

adv
  • In a callous manner; done without regard to others' sensitivities. 

inattentively

adv
  • In an inattentive or careless manner: Of or pertaining to a lack of attention; not paying attention. 

How often have the words callously and inattentively occurred in a corpus of books? (source: Google Ngram Viewer )