In Chapter 6, Jem and Dill plan their nighttime raid on the Radley yard, and Scout opposes their plan out of fear that Boo Radley will track them down and kill them. After the boys explain to Scout that they simply plan on sneaking into the Radley yard and peeking through their windows to get a look at Boo, she attempts to dissuade them. Jem responds by telling Scout,
"Scout, I’m tellin‘ you for the last time, shut your trap or go home—I declare to the Lord you’re gettin’ more like a girl every day!" (Lee, 53).
Jem's comment insults Scout, who is a tomboy and prides herself on hanging out with her older brother and Dill. Jem knows that Scout is embarrassed to be referred to as a "girl," which is synonymous with the word sissy, and so she will stop complaining about their risky plan. After Jem accuses Scout of acting like a girl, Scout mentions that she has no other choice than to join the boys on their nighttime raid. The children then proceed to sneak into the Radley yard and barely escape after Nathan Radley runs out onto his back porch wielding a shotgun.