When you do something carelessly, you are neither cautious nor meticulous. A synonym for do carelessly could be "rush," where you perform an action quickly and carelessly without paying attention to the details. Another synonym could be "neglect," which means that you do not give the necessary attention or care to something or someone. A third synonym for doing something carelessly could be "haphazardly," where you execute an action without any clear plan or order. Other synonyms include "recklessly," "heedlessly," "irresponsibly," and "sloppily." All these synonyms convey the same idea of doing something without proper care and attention, often leading to hasty and often incorrect actions.