Drafty is the American spelling of British draughty. A drafty room or house lets thin streams of cold air in through gaps — around a window, under a door, in an old wall. People complain that a room is drafty in winter; they mean it feels leaky and chilly, not that there is a strong wind inside. The air itself is a draft in American English, a draught in British English. Though actually, American draft is a busy spelling: it also means a first piece of writing and a call-up into the army. Drafty only belongs to the air-in-the-room sense. You would not call an essay drafty, and you would not call a soldier drafty. A new, tight building is usually not drafty; an old wooden house often is.