careless

marked by lack of attention or consideration or forethought or thoroughness; not careful; "careless about her clothes"; "forgotten by some careless person"; "a careless housekeeper"; "careless proofreading"; "it was a careless mistake"; "hurt by a careless remark"

effortless and unstudied; "an impression of careless elegance"; "danced with careless grace"

(usually followed by `of'') without due thought or consideration; "careless of the consequences"; "crushing the blooms with regardless tread"