Careless/ˈkerləs/ Definition 1 of 3Pro Tip 1/3Attention to Detail Careless often implies missing small but crucial details. Because of his careless review, he overlooked the error. Pro Tip 2/3Negative Outcome Using 'careless' suggests an action led to a negative result. His careless planning resulted in a failed event. Pro Tip 3/3Avoid in Formal Apologies When apologizing formally, use 'unintended mistake' instead of 'careless.' I apologize for any unintended mistakes in my work.