An instance of such failure, carelessness, or indifference
The state or fact of being neglected:
Great enthusiasm or lack of restraint:
A careless, often reckless disregard for consequences
Find another word for thoughtlessness. In this page you can discover 22 synonyms, antonyms, idiomatic expressions, and related words for thoughtlessness, like: inattention, oversight, heedlessness, negligence, carelessness, neglect, abandon, disregard, inconsiderateness, inconsideration and unthoughtfulness.