This question is an off-shoot of this Meta question focused on the deletion, and consequently on the closure, of a particular single-word-request question.
The question being discussed there was arguably too broad, though that seems to be in dispute to some degree. But as I submit in my answer there, many single-word-request questions are as arguably too broad yet they are left open.
What term means “one who enjoys learning”? (9 answers)
Word for “only caring about oneself ” (14 answers)
It seems to me that a standard for broadness on single-word-requests is not well-established. Must a question have an easily acceptable, single answer? Should questions that receive more answers than others be considered too broad to a greater degree? Should upvotes or popularity of the question have any bearing for or against closure?
Regarding the necessity of an easily acceptable, single answer, how would this be judged in as objective a fashion as possible when considering close-votes?
Why do I think there should be a widely-accepted standard?
It seems to me like people answering a question, and who are familiar with the rules for what is on- and off-topic, have a reasonable right to judge whether the question they're answering is likely to be closed or not. Since closed questions are subject to deletion at any time, it would be frustrating to a user to put in the effort to answer a question that seems to be a good question by the general standards of the site, only to have the question and their diligent answer deleted later on.
For that reason, I'm somewhat skeptical of the argument that questions which attract a huge number of answers are therefore somehow objectively more off-topic. The rules for broadness say:
There are either too many possible answers, or good answers would be too long for this format. [emphasis mine]
I'm not sure the number of answers that show up over a period of time is an accurate reflection of whether there are too many "possible" answers, especially on questions that garner a plethora of copy-paste one-liners from new users, repetitive answers by users who haven't perused the existing ones, or other Low Quality answers. A questioner can't control how many low quality answers they'll get, and I don't know that those answers really measure the quality of the question. Furthermore, an early responder posting a good answer has no way of knowing that the question would be off-topic for this reason until those answers appeared. It seems to me that off-topic questions should be off-topic questions from the beginning.
My impetus for this question is fairness and consistency. Fairness because without a predictable standard for whether a question is on-topic, users could feel their questions or answers were unfairly deleted while similar questions or answers were not (See the linked Meta question again).
However, I recognize that this site is for the broad community of visitors, not just users who post, so I also emphasize consistency for its own sake. Even if users can't expect their questions to be closed on a purely "fair" basis, which in a democratic forum, they surely can't, it still seems like a worthy aspiration to attempt to our best ability to close questions in a consistent way. That has the added benefit of providing a guide by example to other users as to what kinds of questions are on- and off-topic. That in turn can promote better questions, better answers, and a better experience for both users and visitors of the site.