Daft means silly, foolish, or not thinking straight. It’s often an affectionate dig at your mate for doing something daft, rather than a proper insult. Tone does the heavy lifting, it can be gentle teasing or a sharper put-down. All over the UK, and in Yorkshire you’ll hear it amped up as daft as owt.
"Our Kev tried barbecuing in t’rain. I said, Ay up, tha’s daft as owt. Now we’ve got soggy coals and half-raw sausages."