what; what sort of thing
Used in questions or statements about the nature or content of something, often with a slightly formal or serious tone.
What happened?
He tackles everything seriously.
Used with particles like も or でも to mean 'everything' or 'anything'; often in affirmative or negative contexts.
See also: 何事も
Everything is an experience.
There is a reason for everything.
what on earth?; what's the meaning of this?
Used as a rebuke or exclamation when questioning someone's actions or a situation, often with a tone of surprise or anger.
What on earth is this?!
What's the meaning of that outfit?!
There was a loud noise—what on earth is going on?
He approaches everything seriously.
No one knew what had happened in the village.