Here's a simple example of the problem:
"What is a word that describes someone who covers the ground quickly"
What's wrong with that? Well we don't know what part of speech is required. We could give a noun "runner" or we could give an adjective "speedy". Both of these "describe" the person.
Given that people almost never say whether they want a noun or an adjective, or some other part of speech, is there some way we can tie them down?
I offer an obvious possibility. It is to get rid of the single-word tag and instead have noun, adjective, and verb tags.
What do people think?