heedlessly vs irresponsibly

heedlessly

adv
  • In a heedless manner: with unawareness; without noticing; carelessly, inattentively. 

irresponsibly

adv
  • In an irresponsible manner; so as to be irresponsible. 

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