Afire and the word that will appear as the next entry in this project, aflame, are synonyms. They mean to be burning, i.e. on fire or in flames. This is going to make it difficult for me to come up with much that is different to say about the two adjacent words.
Afire offers me one advantage in that it is occasionally used in a colloquial sense that is less common for the word aflame. Sometimes people will say “she’s afire” in the same way they might say “she’s on fire.” When they do, they usually don’t mean that the person in question has, in fact, caught fire. Instead, they usually mean that she is hyperactive, normally in the pursuit of the achievement of an objective.
In this sense, if an arsonist sets a lot of fires within a short period of time, you might say, “he’s afire.” But that’s neither here nor there. Hopefully, the arsonist is neither here nor there as well.
OK, OK. I know it’s a stretch, but give me a break. I’m soon going to be hitting the 400-word mark in this project. Some of the entries are going to be a little thin. If you’re going to hate me for that, save it up for aflame, which is coming next. I suspect I’ll have even less to say about it.