Lacknowledge
When two people see each other in public and decide to pretend they don't know each other, like they're both hiding from the same monster.
At the mall, my ex and I saw each other and walked straight past like we were strangers.
My cousin and I bumped into each other at the grocery store and ignored each other like we were in a war.
My teacher and I saw each other at the movies and acted like we didn't know each other.