In Chapter 25 of To Kill a Mockingbird by Harper Lee, what causes Scout to comment that Jem was acting more like a girl every day? What definition of "girl" does she imply?
On a particularly warm fall night, Jem and Scout are reading while laying on their cots on the back porch. Scout notices a roly-poly bug crawling around on the floor. She observes it for some time then positions herself to smash it when Jem stops her.
Jem, as usual during this particular part of the story, is in a bad mood and scowls at Scout to stop her quest to end the bug's life. By this time in the plot, Scout has grown weary of Jem's moods and wishes that he would move on past his moodiness. When Scout asks why she should not kill the roly-poly, Jem simply states that the bug has done nothing to bother Scout and so should not be killed.
This annoys Scout who has been chastised off and on throughout the story for behaving too much like a girl. Because Scout is annoyed at Jem, she states that it is Jem who is behaving more like a girl and not her. This reference to Jem's objection to the bug being killed implies that Scout refers to the definition of a girl as one who is sensitive and caring, even to bugs.
While waiting to go with Atticus to see Helen Robinson, Jem urges Scout not to kill a roly-poly bug. Jem has been deeply affected by the events of the trial. He understands the senslessness of Tom's conviction and death, and he feels sensitive about the innocent. Scout, after years of being around and watching boys, believes that to be a "girl" is to be sensitive and "tender-hearted". A girl is sensitive and does not crush bugs because bugs are living beings. Therefore, she connects Jem's concern with girl-like behavior. It will be some time yet before Scout matures in the way that Jem has and begins to understand the cruelty of the world and to appreciate the beauty in it.