Hussar
Legend
The 4e Avenger is an unarmored holy warrior that added wisdom mod to defense and attack and damage, and had an at-will version of the vengeance paladin's channel divinity Oath of Emnity. They specialized in being hard to get away from, and punishing your for trying, but in a striker way! It was fun.
Fair enough. I have no real issues with repurposing names though. It just doesn't bother me overmuch, and, considering how much actual classes have been reworked in 5e, it really doesn't bother me.
Avenger is just a cool name. Then again, Vindicator might work as well. It's a synonym, sounds pretty cool and gets the point across. Or perhaps Guardian?
Actually, thinking about it, I like Guardian. It has all the right connotations, doesn't imply any sort of disparate power relation between the PC and other classes, and hits the right notes for a sort of "warrior" class.
I nearby nominate Guardian for the next warlord.