A familiar or slang abbreviation of certain words, as confidant, conundrum, conformist, contract.

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1825.  C. M. Westmacott, Eng. Spy, I. 30. We were soon the most inseparable cons.

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1841.  Fraser’s Mag., XXIII. 59. Puns, riddles, cons, etc. are low.

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1882.  Banner (newspr.). To what denomination the family belongs, whether they are Cons or Noncons.

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1889.  Pall Mall G., 24 Aug., 2/1. About the ‘contract system’ … The men get some ‘con,’ as they call it, or ‘plus’ pay, but for every penn’orth of ‘con’ the contractor gets two penn’orth of work out of them.

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