1. very careful about details and wanting everything to be correct and perfect
2. having very high standards and being difficult to please

Examples

• She is fastidious about keeping her desk organized.
• The chef was fastidious in selecting only the finest ingredients.
• He’s too fastidious about his appearance, spending hours getting ready.
• The editor was fastidious about grammar and punctuation.
• Her fastidious attention to detail made her an excellent proofreader.
• The restaurant caters to fastidious diners who expect perfection.
• He kept a fastidious record of all his expenses.