Run-in (noun)

1. A confrontation or argument, especially an angry one.
2. A dispute or altercation.
3. An encounter or meeting, especially an unpleasant or hostile one.

Origin:

Late 19th century: from run in "interfere".

Examples:

1. He had a run-in with his boss.
2. The two friends had a run-in over the phone.
3. The police officer had a run-in with the suspect.
4. The teacher had a run-in with the student.
5. The customer had a run-in with the store clerk.