on earth
idiomPart ofearth
on earth — idiom
1. used after question words like 'how', 'why', 'what', 'who', 'where' to add stron
1.idiom
Definition
used after question words like 'how', 'why', 'what', 'who', 'where' to add strong emphasis, usually showing surprise, anger, or great interest
Example
How on earth did you manage to finish the entire project in one night?
Why on earth would anyone pay so much money for an old, broken bicycle?
What on earth is that strange noise coming from the basement?