When a (white) man has a face that looks like a farmer's, or that one of his previous ancestors could have been a farmer, very plain faced, with smaller eyes, a strong triangle at the eyebrows when wincing, and usually a shaved head, receding hairline, or buzzed head.
If you put a pair of overalls and/or a farmer hat and/or in front of a tractor, they would look the part.
Corey Taylor of Slipknot/Stone Sour, James Hetfield of Metallica, and Farron Cousins of The Ring of Fire are excellent examples of Farmer Face
Girl: Corey Taylor is soo hot! What do you think, babe?
Guy: Uh, he totally has farmer face. Throw him in some overalls posing in front of a tractor and he'd pass.
Girl: God dammit, you're right. You ruined him for me ð
Guy: ð¤·ð» âï¸