Unpremeditation

The man who can carry through a carefully premeditated scene with an air of complete unpremeditation has an immense advantage. "Mr. Lester," he began, "I understand that you are the administrator of the estate of the late Philip Vantine?" "

With a gesture as automatic as drawing breath, he jerked out his watch and looked at it, apparently to make sure of catching his trolley, although his valedictory was poured out with such a passionate unpremeditation that the action must have been involuntary and unconscious.

[…] on the plane, I had taken to Jimmie also because of his seeming unpremeditation in talking to me in the first place.