“Sir,” said Harry, reminding himself irresistibly of Voldemort, “I wanted to ask you something.”
“Ask away, then, my dear boy, ask away. . . .”
In this sentence, I don't know what does 'away' mean?
I understand what 'away' means in these sentences:
Go away.
Jason was away on a business trip.
But when we use 'ask away'... What nuance of meaning of the word 'away' is here?
Is it possible to omit 'away'? Would it still be the same meaning?
People understand Ask away by analogy with certain other familiar sentences with away.
Soldiers shout this when dropping bombs from an airplane (see, for example, this book):
Bombs away!
By itself, the word away means "located somewhere else" or "at a distance". In the phrase bombs away!, it suggests movement: "going somewhere else". Bombs away! announces that the bombs have just been released and are now in motion, though many non-soldiers think it's a command to release the bombs. Either way, it refers to the bombs' being "on their way" to their destination, freed from the plane, moving away from the plane, soon to cause damage when they hit their target. A similar sentence is Torpedo away!, said after launching a torpedo (example).
Soldiers say this to mean, "Start shooting your guns, and don't hold back":
Fire away!
Fire here means to shoot a gun. Here, away has the same connotation as in Bombs away!: that you are releasing something that will fly "away" and do damage. It also suggests immediacy and a lack of inhibition. You should eagerly "release" your potential firepower "right away" and hold nothing back.
A metaphorical usage of Fire away! appears in this well-known song from 1980: "Hit me with your best shot—fire away!" The literal meaning is: "Hit me as hard as you can. I am tough enough to withstand it." The speaker is confidently challenging the listener to a fight.
People commonly say Fire away! metaphorically to mean "Ask me all the questions that you want to ask", especially when these questions might be difficult for the speaker to answer, either because they might dig into something embarrassing to the speaker or because the speaker might not know the answer.
When you say:
Ask away!
you are telling your listener to ask any question or questions that the listener wants to ask. The nuance of meaning comes from the way this sentence echoes sentences like those above (and some others, but hopefully that's enough). It suggests that the listener should not hold back or be inhibited about asking these questions, even though the questions might be difficult or upsetting for the speaker.
Ask away! doesn't necessarily suggest that the questions will hit the speaker like bombs or bullets. But this sentence is especially appropriate in situations like a meeting where the speaker must answer hostile questions about something unpleasant or embarrassing, like the "rapid-fire questions" mentioned in this difficult situation. In any sort of context, Ask away! suggests that the speaker is confident that he will be able to address whatever the listener "throws at him". It can also be a way to reassure the listener that the speaker won't take offense to a question.
Notice in the story that the listener, Slughorn, is upset by the question. He suddenly switches from affable confidence to fear. The question appears to hit him pretty hard.
Away has quite a few different meanings, and can be both an adverb and an adjective.
In the context of "ask away", it is an adverb that means "without hesitation".
You could omit the "away" and just say "Ask then, my dear boy, ask."
Away here is used to incite/encourage your interlocutor to do it.
Ask away thus means "Well then go for it, ask your question !". This relates especially well to the passage you quoted from Harry Potter.
In English, prepositions/adverbs can literally change a verb's meaning, and your only way to understand most of them is to bathe yourself in English everyday through series, talking with English people and may be even travelling to an English-speaking country if you have the means.
My native language is not English. But as far as I understand the sentence, whether it's ask away or fire away, the "away" in these sentences mean like "please", or "just do it!"
In the phrase "ask away", I've always thought the word "away" does refer to a distance.
Specifically, it refers to the "distance" from the realm of assumable acceptability. For instance, this may refer to questions that seem to be quite "far" from an expected topic (like being "off topic" from a discussion that has already active), or which are quite "far" from the realm of commonly tolerated protocol (such as asking a question about a sensitive subject, or asking a person who isn't the regular recipient of such a question). If a person wants to ask a question that is within the realm of acceptability, then they could presumably ask without needing an invitation. However, in some circumstances, a potential asker might say:
"Can I ask you a question about something else, about another subject?"
(and the response could be...)
"Ask away"
The phrase may also refer to the idea to "proceed" and "go ahead". For instance, with the term "fire away" (referring to shooting a gun, mentioned by some of the other answers), it means that you don't need to limit yourself to some confines/limits about when a person is not supposed to fire. "Go" ahead, and do it. And, don't "come back" whining about things if things don't happen as expected.
Given that my answer has used the words "distance", "far", "off", "within", "proceed", "go", and "come", using the word "away" feels like a quite natural fit to the numerous other spatial terms.
Update edit: added one word to evidence in prior paragraph, and added formatting for easier clarity
It is short for the phrase: "Ask away to your heart's content".
