The term 'in a casual manner' can be expressed in three different ways: OFFHANDEDLY (11 letters), idly (4 letters), and laxly (5 letters). OFFHANDEDLY means to do something without much thought or preparation, while idly implies doing something in a relaxed and uninterested way. Laxly, on the other hand, suggests doing something in a careless or negligent manner. All three words describe an action that is done casually and without much effort.