unpremeditation means lack of premeditation; spontaneity. Lexicurio rates it Sui generis — a strength score of 88 out of 100.
noun
- Lack of premeditation; spontaneity.“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?" "”