"Nancying" is a term that refers to someone who is overly fussy or annoyingly particular about things. There are various synonyms that can be used in place of this word. One such synonym is "fretful," which means overly anxious or worried about something. Another term that can be used is "pedantic," which describes a person who is overly concerned with minor details and rules. "Fastidious" is another synonym, which means extremely attentive to cleanliness and tidiness. "Persnickety" is also a term that can be used, which means being too concerned with small and unimportant details. All these synonyms effectively convey the same meaning as "nancying".