IPA: /ˈfʌsiər/
KK: /ˈfʌsiər/
More particular or hard to please than usual; showing excessive concern about details or preferences.
She became fussier about her food choices as she got older.
Fussier → It is formed from "fussy" (from the early 19th century, possibly derived from the dialectal term "fuss" meaning to fuss or be overly concerned) and the suffix "-ier" (meaning more). The word "fussier" means more fussy or more particular about details.
Think of someone who is 'more concerned' ('fussy') about details, which is what 'fussier' describes.