Fussier is an adjective that describes someone who is very particular and demands a lot of attention to detail. Some synonyms for fussier include pickier, choosier, and more meticulous. Other synonyms might include more fastidious or more particular. These words all describe someone who is very precise and may take longer to make decisions or complete tasks because they are carefully weighing all of their options. While some may interpret fussier as a negative quality, it can also be seen as a positive trait in someone who is very attentive and has high standards for their work or surroundings.