>vindicate vs vindictive

I don't think this is a good example of cognates diverging in meaning. They're both more or less kinds of avenging or counter-attacking. When you vindicate something you are responding to some attack made against it, and when something is vindictive it responds to attacks with attacks of its own.

Thrift was formerly a word for profits, now it makes sense. But I recognize the snowclone as a popular 16th century way to form personal verb-noun descriptors like cutpurse, upstart, sawbones, spoilsport, dreadnought. This is still productive because midwit is a recent addition. (Eh, I suppose mid isn't a verb, but I think it's the same pattern.)