The quality of looking and sounding too pleased with yourself. A smug person has decided they are right, or clever, or lucky, and lets you see that they know it — often with a small closed smile. Smugness is that whole attitude, treated as a thing you can point at: "I couldn't stand the smugness in his voice." It is almost always a criticism; nobody says it about themselves except as a joke. Two things separate it from ordinary pride. First, it is quiet. A boastful person tells you loudly; a smug person just sits there radiating it, and that silence is part of what annoys people. Second, it usually comes with comparison — the smug person is pleased partly because someone else got it wrong, lost, or didn't see it coming. So it turns up a lot after arguments ("and then he was insufferable, all that smugness"), in politics and sport writing about winners, and in reviews of films or books whose makers seem too impressed with themselves. English speakers also apply it to things, not just people: a smug little town, the smugness of a company's advertising, meaning the thing gives off that self-satisfied feeling. Being called smug stings more than being called proud, because it says your good opinion of yourself is showing.