1) Anyhow 2) Extravagantly 3) Hastily 4) Heedlessly 5) Incautiously 6) Irresponsibly 7) Laxly 8) Lazily 9) Merrily 10) Neglectfully 11) Raffishly 12) Rakishly 13) Recklessly 14) Thoughtlessly 15) Unwisely 1) Badly 2) Heedlessly 3) In a cavalier fashion 4) In a cavalier manner 5) In a lax way 6) In a rakish manner 7) In an informal way 8) Inconsiderately 9) Indifferently 10) Indiscreetly 11) Nonchalantly 12) Offhandedly 13) Poorly 14) Relaxed 15) Sloppily 16) Tactlessly 17) Thoughtlessly 18) Unceremoniously 
• (adv.) In a careless manner.
Care'less·ly adverb In a careless manner. 
[adv] - without care or concern
adverb without care or concern; `carelessly raised the children`s hopes without thinking of their possible disappointment`