aggression
aim
armed
background
backpack
blackboard
chalkboard
child
children
classroom
concept
criminal
danger
desk
education
firearm
free
gun
kid
kill
law
learn
lesson
life
murder
object
pistol
prevention
problem
protection
protests
punishment
pupil
risk
safety
save
school
security
shooting
social
stop
study
table
terrorism
threatening
underage
victims
violence
weapon
wooden