Over-particular, often used to describe someone who is excessively fussy or fastidious, has a few antonyms. The opposite of over-particular could be "easygoing", "laid-back", or "carefree." If someone fails to pay attention to detail and is more relaxed in their approach, they could be described as "casual". Other antonyms could include "flexible", "adaptable", or "unconventional". These words convey a sense of openness and lack of rigidity, qualities that are usually absent in those who are over-particular. Being over-particular could lead to perfectionism and procrastination, while embracing its antonyms could lead to a more relaxed and balanced lifestyle.