a. [ Compar. Muggier superl. Muggiest. ] [ Cf. Icel. mugga mist, mugginess. Cf. 4th Mold. ] 1. Moist; damp; moldy; as, muggy straw. [ 1913 Webster ]
2. Warm, damp, and windless; uncomfortably hot and humid; sultry; as, muggy air, weather. [ 1913 Webster ]