1. to answer or respond to someone without paying attention, care, or consideration; to give a hasty or thoughtless response
He replied carelessly to the important question without thinking about the consequences.
Ele respondeu descuidadamente à pergunta importante sem pensar nas consequências.
2. to respond in a manner that shows lack of concern or attention to detail
She replied carelessly to the email, making several grammatical errors.
Ela respondeu descuidadamente ao e-mail, cometendo vários erros gramaticais.