Careless

1. Without thought or purpose; without due care; without attention to rule or system; unstudied; inconsiderate; spontaneous; rash; as, a careless throw; a careless expression.
2. Not receiving care; uncared for.
3. Free from care or anxiety. hence, cheerful; light-hearted.
4. Having no care; not taking ordinary or proper care; negligent; unconcerned; heedless; inattentive; unmindful; regardless.