Nature of Aversion

I was reading this answer, in which an essay is cited. In this essay, *Freedom From Fear*, an example is given of a hunted deer which experiences anger, and thus aversion. In contrast, the desire to escape isn't aversion, but considered potentially skillful. I have always thought aversion involves aversive states such as avoidance from painful experiences. **Is aversion strictly about anger, and irritation? Does it have nothing to do with avoidance (though the English term somewhat suggests this)?** In sum, I wonder what the nature of aversion actually entails and encompasses.