'fleshiness' originates from English, specifically the word 'fleshy' combined with the suffix '-ness', where the Old English root 'flǣsc' meant 'flesh'.

'fleshiness' changed from the adjective 'fleshy' (from Middle English 'flesch(i)', from Old English 'flǣsc' meaning 'flesh') and formed the noun with the addition of the suffix '-ness' in later English.

Initially it meant 'of or pertaining to flesh' (description of flesh or body); over time it evolved into the noun meaning 'the condition or quality of having much flesh; meatiness; (also) a sensual or carnal quality'.