clutced her notebook in the other hand as though it were a flyswatter is this a similie?

No, the phrase "clutched her notebook in the other hand as though it were a flyswatter" is not a simile. A simile is a figure of speech that compares two different things using the words "like" or "as." In this particular phrase, there is no direct comparison using "like" or "as." Instead, it describes the action of clutching the notebook in a certain manner (as though it were a flyswatter), without explicitly stating it as a comparison.