"More cornfed" is a phrase that describes someone who is big and sturdy, often from a rural or farming background. The antonyms for "more cornfed" could be slender, petite, delicate, or refined. These words suggest a leaner, more elegant appearance or demeanor, perhaps synonymous with a city or metropolitan upbringing. Other antonyms might include weak, frail, or slender, reinforcing the idea of a smaller, less robust physique. Overall, the antonyms for "more cornfed" paint a picture of someone with a decidedly different body type than the robust and hearty connotation of the phrase.