First off, I wouldn't vote to close either of these questions as Non-Constructive, but I might be tempted to cast a close vote as General Reference.
When I see such a yet-to-be-answered question posted on ELU, there are three ways I might handle it:
1) I might answer the question
2) I might leave an answer to the question as a comment
3) I might vote to close the question
In cases where I feel like the question ought to be closed, I'll often try to provide an answer before casting a vote, either as an answer or in a comment. After all, I don't begrudge someone for asking a question when they don't know the answer. For example, consider the O.P.'s beheading question. If I saw that question with no comments and no answers, I might opt to answer it before casting a close vote. But if the question already had two answers, like:
That's called beheading; from NOAD:
behead (verb) cut off the head of (someone), typically as a form of execution
That might depend on the device used to chop off the head. If the person is being executed on a guillotine, then there's the verb guillotine. There's also the word decapitate, which is more general, but it could also be used in your context, as in, The king was decapitated on the guillotine.
then I wouldn't have a problem casting a close vote, seeing that the question has been satisfactorily answered. Moreover, I might leave a comment to a reverse dictionary, if I think that might be a helpful tool for the O.P. with similar questions in the future.
In other words, I don't consider it an affront to answer a qusetion when it is General Reference, but I don't think it's necessarily a bad practice answer a General Reference question, either. The question has been answered; there's really nothing to add. That's why, on occasion, I've even cast close votes right after I've answered the question!
A close vote doesn't necessarily mean, "We don't like your question, go away." It means, "This question doesn't need to remain open." That could be because it was a crappy question (in which case I'd probably also vote to delete, after it was closed), or it could mean that a basic question has been satisfactorily answered, so there is no need for it to remain open.