This is the 7170th most frequent Japanese word.
一体全体
"One whole entity; (intensifier) what in the world, what on earth."
Used to emphasize a question and express incredulity.
一体全体何が起こったのですか。
What in the world happened?
Highlights confusion and disbelief toward understanding his explanation.
彼の説明は一体全体どうなっているのか、全く理解できない。
I absolutely can't understand how in the world his explanation makes sense.
Expresses amazement when asking for explanation regarding an achievement.