A mistake you make because you aren't really paying attention is an example of a careless mistake.
- without worry; carefree; untroubled
- not paying enough attention; not thinking before one acts or speaks; neglectful; heedless; inconsiderate
- done or made without enough attention, precision, etc.; not painstaking or thorough
- artless; unstudied: a careless grace
Origin of carelessMiddle English careles from Old English carleas: see care and -less
- Taking insufficient care; negligent: a careless housekeeper; careless proofreading.
- Marked by or resulting from lack of forethought or thoroughness: a careless mistake.
- Showing a lack of consideration: a careless remark.
- Unconcerned or indifferent; heedless: careless of the consequences.
- Unstudied or effortless: danced with careless grace.
- Exhibiting a disposition that is free from cares; cheerful: a careless grin; a careless wave of the hand.
(comparative more careless, superlative most careless)
From Middle English careles, from Old English carlēas (“careless, reckless, void of care, free from care, free”), equivalent to care + -less.