carelessly vs facetiously

carelessly

adv
  • Giving the appearance of carelessness; relaxedly. 

  • Done without care or attention; inattentively. 

facetiously

adv
  • In a facetious or flippant manner; in a manner that treats serious issues with deliberately inappropriate humor 

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