A frenemy by any other name

It's well known by now that Merriam-Webster added the word "frenemy" to its venerable dictionary.  Discuss amongst yourselves whether this word warrants inclusion.  I'm more curious about the official definition, which is " one who pretends to be a friend but is actually an enemy."

I've always used this word more in the second sense that is reported by Wikipedia: "a partner who is simultaneously a competitor."

I guess there is room for both meanings, but they seem very different to me.  One suggests that the friend is not a friend at all.  Whereas the second definition, which admittedly speaks more to corporate relationships, suggests a relationship that is more nuanced, where there is both good and bad.