Fastidious/fæˈstɪdiəs/ Definition 1 of 3Pro Tip 1/3Hard to Please Use 'fastidious' to describe people who have high standards and are rarely satisfied. The fastidious boss often made employees redo their work. Pro Tip 2/3Detail-Oriented Implies an orientation towards even the smallest details, possibly to the point of obsession. Her fastidious nature made her an excellent editor. Pro Tip 3/3Not Always Negative Can be positive. It might show thoroughness or being conscientious in tasks. His fastidious approach ensured the event's success.