Inverse-Weak modifier needs a name

[Umlaut]

I was thinking about exactly this modifier a while ago and didn't know what to call it either. I feel like the difficulty of finding a logical converse to "Weak" reveals that Weak was always kind of a weird name for that modifier in the first place, but Vain is as good as anything (it's short and easy to remember, which probably matters more than making perfect sense does).

[Umlaut]

Prideful would avoid the positive connotations of Proud. But at that point I think I just like Vain better.