IPA: //ˈprɪsi//
KK: /ˈprɪsi/
More concerned with being proper or neat in a way that can seem overly fussy or affected.
She dressed in a prissier manner than her friends, always choosing the most formal outfits.
Comparative: prissier
Superlative: prissiest
Prissier is derived from the word "prissy" (from the 19th-century slang, possibly a diminutive of "precious"), which means overly proper or affectedly dainty, combined with the comparative suffix "-ier" (meaning more). The word "prissier" means more prissy or more affectedly proper than something else.
Think of someone being 'more proper' or 'more affected' — that's what prissier means.