plethorically UK /plɛˈθɒɹɪkli/US /pləˈθɔɹək(ə)li/ adverb1 •In a plethoric manner: excessively, overabundantly.Old Chewke, the plethorically wealthy retired timber-merchant, formerly of Riga, went purposely two hours later to the Union Club that morning. — 1861 formsmore plethorically · most plethorically