Diversionary foreign policy is when a leader or government uses foreign policy or military actions to distract their people from problems at home, like bad decisions they made or difficult situations they cannot control.
Imagine it's your bedtime and you don't want to sleep, your mom might try to distract you by reading you a book or counting stars on the ceiling. Diversionary foreign policy is like that, but instead of counting stars, the leader might start a war or send troops to another country. They hope that by doing this, people will stop thinking about their problems at home and focus on the new, exciting issue instead.
Unfortunately, this can be dangerous because playing with foreign policy and military issues can lead to real war and harm innocent people. It is important for leaders to solve issues at home without using war or military intervention as a distraction.