deadpan

from WordNet (r) 3.0 (2006)

deadpan
    adv 1: without betraying any feeling; "she told the joke
           deadpan"
    adj 1: deliberately impassive in manner; "deadpan humor"; "his
           face remained expressionless as the verdict was read"
           [syn: {deadpan}, {expressionless}, {impassive}, {poker-
           faced}, {unexpressive}]

from Moby Thesaurus II by Grady Ward, 1.0

22 Moby Thesaurus words for "deadpan":
      blank, cold-bloodedly, coldheartedly, coldly, dispassionately,
      empty, expressionless, fishy, glassy, heartlessly, impassive,
      in cold blood, inexpressive, poker-faced, spiritlessly,
      unemotionally, unexpressive, unfeelingly, unpassionately, vacant,
      with dry eyes, wooden

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