If you describe a person or their behaviour as daft, you think that they are stupid, impractical, or rather strange. He's not so daft as to listen to rumours Don't be daft! = silly
[ 'daft also 'däft ] (adjective.) 14th century. Middle English dafte gentle, stupid; akin to Old English gedæfte mild, gentle, Middle English defte deft, Old Church Slavonic podobati to be fitting.