Feat name: Ankle Breaker

You are as light on your feet as you are sharp of mind, a trait you put to good use in out maneuvering your opponent and leaving them in the dust. 

While in combat, you may, as a bonus action at the start of your turn, prepare to break the titular ankles. Until the end of your next turn, when you provoke an opportunity attack, you feint out of the way, forcing the attacking creature to make a DC 10 (+ your dexterity mod.) saving throw or be knocked prone. You may use this a number of times equal to 1 + your dexterity modifier per long rest. 

Pre requisites: Must have a dexterity score of at least ten

That's suuuuuuuuper weak.

First, I would make the DC include your proficiency bonus. 

Second, there isn't any feature that actually allows you to break their ankles, which seems a bit disappointing. However I understand if that is intentional, as DnD doesn't have rules for attacking specific areas of a target. 

For actually breaking their ankles: As an action, you can attack a prone creature's ankles. Roll to hit. (Maybe use a grapple check instead) On a hit, the target's speed is halved and they cannot stand up.

You do not understand. an ankle breaker is a defensive move in basketball involving a crossover which causes your opponent to fall over. You're not actually breaking ankles

Oh...understandable. still add the proficiency bonus to the DC. Otherwise I think it's good.

thanks!

You don’t mean “titular,” you mean “metaphorical.” Titular means something completely different. I would just not mention “breaking ankles” at all as it’s bound to cause more confusion than not.

Why is it both “as a bonus action” and “at the start of your turn?” It only needs to be one or the other, preferably as a bonus action since things that trigger at the start of your turn are usually damage effects.

It should definitely include PB in the save DC, but the base should be 8+, not 10+. Theses things are always calculated as 8+ability modifier+proficiency bonus.

You never specified if this precludes the opportunity attack working or not.

I agree with most of this, but I did mean titular. titular was once a term used to describe positions which were in name only, meaning there was no power behind it. Now a days, the word can be interpreted as meaning nominal, or referring to the name or title. Either way, it's pointless since I have already posted the homebrew

Quote from I_MAKE_UNBALANCED_HOMEBREW >>

Either way, it's pointless since I have already posted the homebrew

You can still make updated versions. Not that I think it’s bad as-is, I just wanted to point that out.

Really? how?

You click/tap “create new version,” navigate to your creations, edit the new version and republish. It won’t overwrite the old version or anything, but it’ll push the older version to the background. Both versions will still be accessible, so it’s less than ideal, but it’s better than nothing I suppose. Just try not to do it with spells or races as those have special problems when republished. In future, wait until you are 1,000% satisfied with something prior to publishing it.