Particular definition is fairly difficult to understand. It refers to someone who is vitally particular and nitpicking. A persnickety individual tends to be fastidious and has high standards when it comes to standards and flawlessness. Their attention to detail can be perceived as commendable, but it can also intensify unreasonable censure and superfluous dissatisfaction. Being persnickety is typically associated with detailed attention to detail but can also be seen as a type of pedantry.