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S.W.A.K.
S.W.A.K.
A mark of affection on the back of an envelope. Before e-mail, Facebook, and Twitter, people exchanged romantic sentiments by means of handwritten letters. One way to include a final bit of tenderness was to write S.W.A.K. on the back of the envelope. Women often blotted their lipstick over the four letters to emphasize their love.