There’s also a big difference between someone who says, “I’ve looked here and here, but haven’t got a satisfactory answer,” or “source X disagrees with source Y,” and someone who just simply poses a question that can be answered by looking in any decent dictionary. Someone who has shown that they’ve done at least a little spadework of their own upfront will be received better.
But in all cases, a civil and polite response to straightforward queries is preferred to the alternative. (I’m not talking about trolls, to which the best response is silence—flaming a troll just encourages them, as discord is what they are seeking.) A response like “The answer can be found in any good dictionary. Merriam-Webster’s 11th Collegiate says...” That provides the answer and tells them where to look next time. If the same person keeps coming back with similar questions, then a more abrupt, but still civil, response may be appropriate.