adj

• (obsolete) Studiously neat or nice, especially in dress; spruce; affectedly precise; smooth and prim.
  "They be so smug and smooth."

verb

• (obsolete, transitive) To make smug, or spruce.
  "Thus said, he smug'd his beard, and stroked up fair."
• (intransitive) to adopt an offensively self-complacent expression.
  "1899 Ambrose Bierce: Fantastic Fables. Hearing a sound of strife, a Christian in the Orient asked his Dragoman the cause of it. "The Buddhists are cutting Mohammedan throats," the Dragoman replied, with oriental composure. "I did not know," remarked the Christian, with scientific interest, "that that would make so much noise." "The Mohammedans are cutting Buddhist throats, too," added the Dragoman. "It is astonishing," mused the Christian, "how violent and how general are religious animosities. Everywhere in the world the devotees of each local faith abhor the devotees of every other, and abstain from murder only so long as they dare not commit it. And the strangest thing about it is that all religions are erroneous and mischievous excepting mine. Mine, thank God, is true and benign." So saying he visibly smugged and went off to telegraph for a brigade of cutthroats to protect Christian interests."
• (obsolete, transitive, slang) To seize; to confiscate.
• (obsolete, transitive, slang) To hush up.

noun

• (obsolete, Anglo-Chinese) The smuggling trade.
  "Have not they some term by which they distinguish the illicit trade? — They usually call it the Smug-pigeon."