The term 'well-heeled' originated in late 19th-century American slang. Its literal sense referred to a gamecock (a rooster bred for fighting) that was equipped with sharp, effective spurs on its heels, giving it a competitive advantage. This imagery of being properly equipped for a fight was then figuratively extended to a person who is financially equipped or prosperous. The logic of the metaphor evolved from being literally armed for combat to being figuratively furnished with wealth, shifting the domain from physical conflict to financial security.

Structure: well (in a good manner) + heeled (provided with heels) - well: Old English. An adverb meaning 'in a good or satisfactory manner'. In this compound, it functions as an intensifier. - heeled: English. The past participle of the verb 'to heel', here used in a specific slang sense meaning 'furnished or equipped with something'.