Careless mistakes are errors that are made due to negligence or lack of attention. They can range from minor oversights to major blunders. Common terms for careless mistakes include 'SLIPSHOD' (8 letters), which means done carelessly and hastily; 'boners' (6 letters), which are mistakes that are particularly embarrassing; 'lapses' (6 letters), which are temporary failures in concentration; and 'avoidable' (9 letters), which means something that could have been prevented.