Why do native speakers use "vent your anger" rather than "erase your anger"?

Question

Today, I learnt a new phrase:

vent your anger

That means calm someone down.

But I am confused because the word erase also means make something disappear, so I am wondering if the word vent could be replaced by the word erase?

Answer 1

I'm afraid the meaning you were given is not what most people understand by it. Merriam-Webster gives me this definition for vent:

to express (an emotion) usually in a loud or angry manner

When you vent your anger, it is not so much about making the anger disappear, but about letting it out.

I've not often heard about someone erasing their anger, but I would imagine, that they count to ten, and decide not to become visibly, noticeably angry.

Someone who vents his anger will actually shout, swear, hit someone, or whatever else they decide to do to actually show their anger.

They assumption is that after venting one's anger, the anger is less, or completely gone, but the act of venting it is actually showing one's anger.

Answer 2

Specifically regarding the example sentence you quoted in the comments:

We'd better listen to his recounting attentively, so as to vent his anger.

I would say that it does sort of work, insofar as the metaphor makes sense: "vent" can refer to a slow, controlled release of pressure, and it seems sensible that allowing someone to express their anger at you at length, while meekly listening and trying not to arouse any more anger, could indeed sometimes be an effective way to calm down an angry person.

That said, this is definitely not the usual way in which the expression "vent one's anger" is normally used. As oerkelens correctly notes in their answer, that expression usually refers to releasing your own anger, e.g. by shouting, or perhaps even through physical violence.

(It does, sometimes, carry the connotation of safely venting one's anger, e.g. through physical exercise, even when the word "safely" is not explicitly stated. Even in this sense, though, it still clearly refers to expressing your anger, in some manner that offers emotional release, as opposed to bottling it up.)

In particular, when used in this usual sense, it's not possible to vent someone else's anger — you can only vent your own anger, and they can only vent theirs. That said, you can let or help someone else vent their anger, which is what your teacher may have been trying to say, as in:

We'd better listen to his recounting attentively, so as to let him vent his anger.

---

Ps. There are other issues with the sentence you quoted that make it sound less natural. For example, the verb "recount" (in the sense of "tell, narrate, speak", as opposed to "count again"), and its participle "recounting", are quite rare in modern English, and typically only used in the rather specific sense of re-telling a story, or describing a series of past events or experiences in detail. They're not commonly used to describe someone chastising others for their (perceived) failures, or otherwise expressing their anger.

More appropriate words for this situation might include "speech", "criticism", "feedback" (something of a business jargon term) or even "rant" (although that one might not be considered very diplomatic, at least not if there was any chance of the person being spoken of finding out about it). Using those words, the sentence might be rewritten e.g. as:

We'd better listen to his speech attentively, so as to let him vent his anger.

or even:

We'd better let him rant and listen attentively, so as to let him vent his anger.

Also, "attentively", while communicating the intended meaning (of appearing to pay attention and not talking back) clearly enough, is a rather long and awkward word here. I might be tempted to substitute it with, say, "quietly", or maybe even "meekly", or even rephrase the expression entirely, as in:

We'd better let him rant and keep our mouths shut, so as to let him vent his anger.

Also worth noting is that, in modern English, "so as to" is a rather formal expression, and rarely used in casual speech. It could fit in, if the rest of the sentence followed a similarly formal style, but it feels a bit unnatural when juxtaposed with such strongly casual phrases as "rant" and "keep our mouths shut". If that kind of casual spoken style is what you're going for, I'd suggest replacing the "so as to" with just "to", or maybe "and", (so as) to get:

We'd better let him rant and keep our mouths shut, to let him vent his anger.

or perhaps even:

We'd better keep our mouths shut, and (just) let him rant and vent his anger.