[dead.pan] adj (ca. 1928): marked by an impassive matter-of-fact manner, style, or expression "a ~ comedy" -- deadpan adv
[2]deadpan n (ca. 1930) 1: a completely expressionless face
2: a deadpan manner of behavior or presentation [3]deadpan vt (ca. 1942): to express in a deadpan manner -- dead.pan.ner n